1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- This manual is for GNU LibreJS (version 6.0.9.20150616, 16 June 2015),
a GNU IceCat extension to detect and block nonfree nontrivial
JavaScript on webpages.
Copyright (C) 2011 2012 2014 2015 Loic J. Duros
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts. A copy of the license is included in the section entitled
"GNU Free Documentation License". -->
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
<head>
<title>GNU LibreJS 6.0.9.20150616</title>
<meta name="description" content="GNU LibreJS 6.0.9.20150616">
<meta name="keywords" content="GNU LibreJS 6.0.9.20150616">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link href="#Top" rel="start" title="Top">
<link href="#SEC_Contents" rel="contents" title="Table of Contents">
<link href="dir.html#Top" rel="up" title="(dir)">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.indentedblock {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
div.smalllisp {margin-left: 3.2em}
kbd {font-style:oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
pre.smalldisplay {font-family: inherit; font-size: smaller}
pre.smallexample {font-size: smaller}
pre.smallformat {font-family: inherit; font-size: smaller}
pre.smalllisp {font-size: smaller}
span.nocodebreak {white-space:nowrap}
span.nolinebreak {white-space:nowrap}
span.roman {font-family:serif; font-weight:normal}
span.sansserif {font-family:sans-serif; font-weight:normal}
ul.no-bullet {list-style: none}
-->
</style>
</head>
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
<h1 class="settitle" align="center">GNU LibreJS 6.0.9.20150616</h1>
<a name="SEC_Contents"></a>
<h2 class="contents-heading">Table of Contents</h2>
<div class="contents">
<ul class="no-bullet">
<li><a name="toc-Overview-1" href="#Overview">1 Overview</a></li>
<li><a name="toc-Disclaimer-1" href="#Disclaimer">2 Disclaimer</a></li>
<li><a name="toc-Installation-1" href="#Installation">3 Installation</a>
<ul class="no-bullet">
<li><a name="toc-Building-the-Package" href="#Building-the-Package">3.1 Building the Package</a></li>
<li><a name="toc-Installing-LibreJS" href="#Installing-LibreJS">3.2 Installing LibreJS</a></li>
</ul></li>
<li><a name="toc-How-to-Use-1" href="#How-to-Use">4 How to Use</a>
<ul class="no-bullet">
<li><a name="toc-LibreJS-in-action" href="#LibreJS-in-action">4.1 LibreJS in action</a></li>
<li><a name="toc-Complaint-Feature" href="#Complaint-Feature">4.2 Complaint Feature</a></li>
<li><a name="toc-Options" href="#Options">4.3 Options</a></li>
</ul></li>
<li><a name="toc-JavaScript-Detection-1" href="#JavaScript-Detection">5 JavaScript Detection</a></li>
<li><a name="toc-Free-Licenses-Detection-1" href="#Free-Licenses-Detection">6 Free Licenses Detection</a>
<ul class="no-bullet">
<li><a name="toc-Detected-Free-Licenses" href="#Detected-Free-Licenses">6.1 Detected Free Licenses</a></li>
<li><a name="toc-Undetected-Free-Licenses" href="#Undetected-Free-Licenses">6.2 Undetected Free Licenses</a></li>
</ul></li>
<li><a name="toc-Setting-Your-JavaScript-Free-1" href="#Setting-Your-JavaScript-Free">7 Setting Your JavaScript Free</a>
<ul class="no-bullet">
<li><a name="toc-JavaScript-Web-Labels" href="#JavaScript-Web-Labels">7.1 JavaScript Web Labels</a>
<ul class="no-bullet">
<li><a name="toc-Specifying-multiple-licenses-for-a-single-JavaScript-file" href="#Specifying-multiple-licenses-for-a-single-JavaScript-file">7.1.1 Specifying multiple licenses for a single JavaScript file</a></li>
</ul></li>
<li><a name="toc-Adding-a-stylized-comment-in-your-JavaScript-files-and-on-your-page" href="#Adding-a-stylized-comment-in-your-JavaScript-files-and-on-your-page">7.2 Adding a stylized comment in your JavaScript files and on your page</a></li>
</ul></li>
</li>
<li><a name="toc-Installation-Requirements-1" href="#Installation-Requirements">Appendix A Installation Requirements</a>
<ul class="no-bullet">
<li><a name="toc-Mozilla-Browser" href="#Mozilla-Browser">A.1 Mozilla Browser</a></li>
<li><a name="toc-Mozilla_0027s-Add_002don-SDK" href="#Mozilla_0027s-Add_002don-SDK">A.2 Mozilla’s Add-on SDK</a></li>
</ul></li>
<li><a name="toc-LibreJS-Internals-1" href="#LibreJS-Internals">Appendix B LibreJS Internals</a></li>
<li><a name="toc-Tests-1" href="#Tests">Appendix C Tests</a></li>
<li><a name="toc-GNU-Free-Documentation-License-1" href="#GNU-Free-Documentation-License">Appendix D GNU Free Documentation License</a></li>
</ul>
</div>
<a name="Top"></a>
<div class="header">
<p>
Next: <a href="#Overview" accesskey="n" rel="next">Overview</a>, Up: <a href="dir.html#Top" accesskey="u" rel="up">(dir)</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="LibreJS"></a>
<h1 class="top">LibreJS</h1>
<p>This manual is for GNU LibreJS (version 6.0.9.20150616, 16 June 2015).
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">• <a href="#Overview" accesskey="1">Overview</a>:</td><td> </td><td align="left" valign="top">General purpose and information.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Disclaimer" accesskey="2">Disclaimer</a>:</td><td> </td><td align="left" valign="top">Emphasize what LibreJS does and does not.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Installation" accesskey="3">Installation</a>:</td><td> </td><td align="left" valign="top">Installing LibreJS from source.
</td></tr>
<tr><td align="left" valign="top">• <a href="#How-to-Use" accesskey="4">How to Use</a>:</td><td> </td><td align="left" valign="top">How to use LibreJS in IceCat.
</td></tr>
<tr><td align="left" valign="top">• <a href="#JavaScript-Detection" accesskey="5">JavaScript Detection</a>:</td><td> </td><td align="left" valign="top">How LibreJS detects nontrivial Javascript.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Free-Licenses-Detection" accesskey="6">Free Licenses Detection</a>:</td><td> </td><td align="left" valign="top">List of licenses detected by LibreJS.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Setting-Your-JavaScript-Free" accesskey="7">Setting Your JavaScript Free</a>:</td><td> </td><td align="left" valign="top">Information for website owners/maintainers.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Installation-Requirements" accesskey="8">Installation Requirements</a>:</td><td> </td><td align="left" valign="top">Requirements to build and install LibreJS.
</td></tr>
<tr><td align="left" valign="top">• <a href="#LibreJS-Internals" accesskey="9">LibreJS Internals</a>:</td><td> </td><td align="left" valign="top">How LibreJS works under the hood.
</td></tr>
<tr><td align="left" valign="top">• <a href="#Tests">Tests</a>:</td><td> </td><td align="left" valign="top">Test LibreJS and better understand it.
</td></tr>
<tr><td align="left" valign="top">• <a href="#GNU-Free-Documentation-License">GNU Free Documentation License</a>:</td><td> </td><td align="left" valign="top">Copying and sharing this documentation.
</td></tr>
</table>
<hr>
<a name="Overview"></a>
<div class="header">
<p>
Next: <a href="#Disclaimer" accesskey="n" rel="next">Disclaimer</a>, Previous: <a href="#Top" accesskey="p" rel="prev">Top</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Overview-1"></a>
<h2 class="chapter">1 Overview</h2>
<a name="index-overview"></a>
<p>GNU LibreJS —an add-on for GNU IceCat and Mozilla Firefox— detects
and blocks nonfree nontrivial JavaScript while allowing its execution on
pages containing code that is either trivial and/or free.
</p>
<p>Many websites run nontrivial JavaScript on your computer. Some use it
for complex tasks; many use it gratuitously for minor jobs that could be
done easily with plain HTML. Sometimes this JavaScript code is
malicious. Either way, the JavaScript code is often nonfree. For
explanation of the issue, see "The JavaScript
Trap"(<a href="http://www.gnu.org/philosophy/javascript-trap.html">http://www.gnu.org/philosophy/javascript-trap.html</a>).
</p>
<p>If you care about freedom in your computing, and don’t wish to let all
and sundry make you run nonfree programs, now you can prevent it by
using LibreJS.
</p>
<hr>
<a name="Disclaimer"></a>
<div class="header">
<p>
Next: <a href="#Installation" accesskey="n" rel="next">Installation</a>, Previous: <a href="#Overview" accesskey="p" rel="prev">Overview</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Disclaimer-1"></a>
<h2 class="chapter">2 Disclaimer</h2>
<a name="index-disclaimer"></a>
<ul>
<li> LibreJS is not a security tool. Its goal is to detect nonfree nontrivial
JavaScript, and it currently does not detect whether free or trivial
code is malicious or not. Other free Mozilla extensions and add-ons may
be available for this purpose.
</li><li> LibreJS is always a work in progress. If you find a bug, please report
it to <a href="mailto:bug-librejs@gnu.org">bug-librejs@gnu.org</a>.
</li></ul>
<hr>
<a name="Installation"></a>
<div class="header">
<p>
Next: <a href="#How-to-Use" accesskey="n" rel="next">How to Use</a>, Previous: <a href="#Disclaimer" accesskey="p" rel="prev">Disclaimer</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Installation-1"></a>
<h2 class="chapter">3 Installation</h2>
<a name="index-Installation"></a>
<p>You can install LibreJS directly using a generated <samp>librejs.xpi</samp>
file, or by building it from source.
</p>
<a name="Building-the-Package"></a>
<h3 class="section">3.1 Building the Package</h3>
<p>After enabling the Add-on SDK, you should be able to use the <code>make</code>
command to build LibreJS from source.
</p>
<p>After running <code>make</code>, a new file, <samp>librejs.xpi</samp> should be
generated. This is the file that can be installed in a Mozilla browser.
</p>
<a name="Installing-LibreJS"></a>
<h3 class="section">3.2 Installing LibreJS</h3>
<p>To install the add-on for all users, run:
</p><div class="example">
<pre class="example">sudo make install
</pre></div>
<p>or as root:
</p><div class="example">
<pre class="example">make install
</pre></div>
<p>Next time you open a Mozilla-browser as a user of your system, you
should be notified that a new add-on (in this case, LibreJS) as been
installed and whether to allow it to run or not.
</p>
<hr>
<a name="How-to-Use"></a>
<div class="header">
<p>
Next: <a href="#JavaScript-Detection" accesskey="n" rel="next">JavaScript Detection</a>, Previous: <a href="#Installation" accesskey="p" rel="prev">Installation</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="How-to-Use-1"></a>
<h2 class="chapter">4 How to Use</h2>
<a name="LibreJS-in-action"></a>
<h3 class="section">4.1 LibreJS in action</h3>
<p>After installing the add-on, you will see the LibreJS widget in the
add-on bar at the bottom of the browser window. After loading a page,
left-click on the widget to view the deactivated JavaScript code from
the page (both on page and external) and, if applicable, the scripts
that were accepted.
</p>
<a name="Complaint-Feature"></a>
<h3 class="section">4.2 Complaint Feature</h3>
<p>It is very important to complain when a site has nonfree JavaScript
code, especially if it won’t work without that code. LibreJS makes it
easy to complain by heuristically finding where to send the complaint.
</p>
<p>When nonfree/nontrivial code is detected in a page, LibreJS attempts to
find a relevant contact link or email for the website you are
visiting. In order to do so, it will attempt to visit a few links from
the current page (for instance, a link labeled “contact” on the same
domain as the current page, …)
</p>
<p>LibreJS detects contact pages, email addresses that are likely to be
owned by the maintainer of the site, Twitter and identi.ca links, and
phone numbers.
</p>
<p>After LibreJS detects any of the above, a “Complain” tab will appear
on the right of your web browser. When you click on this tab, a large
panel will appear with contact information. Ideally, at the top you will
find the email address of the maintainer, labeled as the “Email you
should use”.
</p>
<p>When you complain to the website for their nonfree nontrivial
JavaScript, provide them with the link to the JavaScript Trap essay so
that they can get more information on what the issue is and how they can
solve it on their own site.
</p>
<p>LibreJS includes a default subject line and body for the complaint email,
with a link to the JavaScript Trap essay. This can be configured in the
LibreJS add-on preferences in your web browser.
</p>
<a name="Options"></a>
<h3 class="section">4.3 Options</h3>
<dl compact="compact">
<dt><em>Whitelist</em></dt>
<dd><p>LibreJS lets you whitelist domain names and subdomains to bypass the
regular JavaScript check. This might be useful, for example, if you are
running your own code in a local web server. In order to add a
whitelisted domain or url, go to Tools >> Add-ons, or press <kbd>Control
+ Shift + A</kbd>. Inside the add-on window, click on <em>Extensions</em>, and in
the list, where you see LibreJS, click on the <em>Preferences</em> button.
You will see an input field labeled <em>Whitelist</em>. In the field,
enter comma-separated domain names. Do not enter the protocol. For
instance to whitelist all the pages of <a href="http://www.gnu.org">http://www.gnu.org</a> and
<a href="https://gnu.org">https://gnu.org</a>, enter ‘<samp>gnu.org</samp>’. To allow all subdomains from
gnu.org, enter: ‘<samp>*.gnu.org</samp>’. This will match such sites as
<a href="http://savannah.gnu.org">http://savannah.gnu.org</a> and <a href="http://audio-video.gnu.org">http://audio-video.gnu.org</a>.
</p>
</dd>
<dt><em>Complaint tab</em></dt>
<dd><p>This specifies whether the complaint tab appears when a site is running
nonfree JavaScript.
</p>
</dd>
<dt><em>Display notifications of JavaScript analysis</em></dt>
<dd><p>This option enables an info bar of realtime JavaScript analysis.
</p>
</dd>
<dt><em>Complaint email subject</em></dt>
<dd><p>Configure the default subject used in complaint emails.
</p>
</dd>
<dt><em>Complaint email body</em></dt>
<dd><p>Configure the default body used in complaint emails.
</p></dd>
</dl>
<hr>
<a name="JavaScript-Detection"></a>
<div class="header">
<p>
Next: <a href="#Free-Licenses-Detection" accesskey="n" rel="next">Free Licenses Detection</a>, Previous: <a href="#How-to-Use" accesskey="p" rel="prev">How to Use</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="JavaScript-Detection-1"></a>
<h2 class="chapter">5 JavaScript Detection</h2>
<a name="index-javascript"></a>
<ul>
<li>LibreJS considers JavaScript on a page nontrivial if any of the
following are true:
</li><li> It makes an AJAX request or is loaded along with scripts that make
an AJAX request,
</li><li> It loads external scripts dynamically or is loaded along with
scripts that do,
</li><li> It defines functions or methods and either loads an external script
(from HTML) or is loaded as one,
</li><li> It uses dynamic JavaScript constructs that are difficult to analyze
without interpreting the program or is loaded along with scripts
that use such constructs. These constructs are:
<ul>
<li> Using the eval function
</li><li> Calling methods with the square bracket notation
</li><li> Using any other construct than a string literal with certain methods
(<code>Obj.write</code>, <code>Obj.createElement</code>, …).
</li></ul>
</li></ul>
<p>In practice, the JavaScript code in your page may be found trivial by
LibreJS if, as a whole:
</p><ul>
<li> It does not define functions and it does not load external scripts
(with the HTML src attribute in a <code><script></code> tag).
</li><li> It does not make AJAX calls.
</li><li> It does not load external scripts with dynamic constructs.
</li><li> It does not use constructs that may be used to do any of the above in
a non-obvious way (use of the <code>eval()</code> method, use of square bracket
method calls, use of concatenation with certain constructs or method
calls, …).
</li></ul>
<p>However, in some instances, you may be required by LibreJS to add a
stylized comment to JavaScript code that may be otherwise trivial.
</p>
<p>When an external file defines a function, it becomes available
to all other external scripts. That is the case if another script
defines a function that makes AJAX calls, when an external script
loads other scripts dynamically (which in turn could also make AJAX
calls, …), or when a script is written with constructs that may do
any of these.
</p>
<p>For instance, if your page contains the following:
</p><div class="example">
<pre class="example"><script src="jquery.js"></script>
<script>
$.doSomething();
</script>
</pre></div>
<p>While <code>$.doSomething();</code> may seem trivial, you will nevertheless
have to add a stylized license comment on your main HTML page because
the external script (in this case jQuery) has been found to define
methods that make AJAX calls. <code>$.doSomething()</code> might make an AJAX call,
and LibreJS does not check for that. The rule of thumb is that when you
use a library or code that handles AJAX, JSON, JSONP, the loading of
scripts dynamically, you should have license mentions for all your
JavaScript files and for your main page regardless. In practice this is
a case that happens very often with code that uses libraries.
</p>
<p>In practice also, the JavaScript code in an external file (an external
<samp>.js</samp> file loaded on your page) may be found trivial if it does not
define functions/methods.
</p>
<p>And in the same manner it will be considered nontrivial if AJAX calls,
dynamic script loading, or non-obvious dynamic JavaScript constructs
are used in another script.
</p>
<p>If your JavaScript code makes AJAX requests, it’s important to get an
accurate <em>Content-Type</em> in the response from the server. For
example, if you’re using JSON, set it to <code>application/json</code>.
This is because LibreJS alters the content of <code>text/html</code>
responses.
</p>
<hr>
<a name="Free-Licenses-Detection"></a>
<div class="header">
<p>
Next: <a href="#Setting-Your-JavaScript-Free" accesskey="n" rel="next">Setting Your JavaScript Free</a>, Previous: <a href="#JavaScript-Detection" accesskey="p" rel="prev">JavaScript Detection</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Free-Licenses-Detection-1"></a>
<h2 class="chapter">6 Free Licenses Detection</h2>
<a name="index-freelicenses"></a>
<a name="Detected-Free-Licenses"></a>
<h3 class="section">6.1 Detected Free Licenses</h3>
<p>In order for a file to be detected as free, the license notice should
appear in a JavaScript file above all code, at the very top of the file.
</p>
<p>For inline JavaScript code inside <code><script></code> tags in HTML pages,
the license notice should appear once per page as a comment inside a
<code><script></code> tag, before all the code in that script. When the only
inline JavaScript code is within element attributes (<code>onload</code>,
<code>onclick</code>), place the license notice in an otherwise empty
<code><script></code> at the top of the page. This is sometimes needed when an
external script performs AJAX calls or embeds scripts dynamically, and
the only inline JavaScript is an event attribute making a method call,
e.g.: <code><body onload="methodCall('remote-data.xml');"></code>
</p>
<p>When people speak of the “MIT license” they mean either the X11 license
or the Expat license. Please see which license the code uses, and label
it accordingly.
</p>
<p>Currently LibreJS checks for the following licenses:
</p>
<ul>
<li> Apache License, Version 2.0
<ul>
<li> Identifier: ‘<samp>Apache-2.0</samp>’
</li><li> URL: <a href="http://www.apache.org/licenses/LICENSE-2.0">http://www.apache.org/licenses/LICENSE-2.0</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:8e4f440f4c65981c5bf93c76d35135ba5064d8b7&dn=apache-2.0.txt</code>’
</li></ul>
</li><li> Artistic License 2.0
<ul>
<li> URL: <a href="http://www.perlfoundation.org/artistic_license_2_0">http://www.perlfoundation.org/artistic_license_2_0</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:54fd2283f9dbdf29466d2df1a98bf8f65cafe314&dn=artistic-2.0.txt</code>’
</li></ul>
</li><li> Boost Software License
<ul>
<li> URL: <a href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:89a97c535628232f2f3888c2b7b8ffd4c078cec0&dn=Boost-1.0.txt</code>’
</li></ul>
</li><li> BSD 3-Clause License
<ul>
<li> URL: <a href="http://opensource.org/licenses/BSD-3-Clause">http://opensource.org/licenses/BSD-3-Clause</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:c80d50af7d3db9be66a4d0a86db0286e4fd33292&dn=bsd-3-clause.txt</code>’
</li></ul>
</li><li> CPAL 1.0
<ul>
<li> Identifier: ‘<samp>CPAL-1.0</samp>’
</li><li> URL: <a href="http://opensource.org/licenses/cpal_1.0">http://opensource.org/licenses/cpal_1.0</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:84143bc45939fc8fa42921d619a95462c2031c5c&dn=cpal-1.0.txt</code>’
</li></ul>
</li><li> Creative Commons CC0 1.0 Universal
<ul>
<li> Identifier: ‘<samp>CC0-1.0</samp>’
</li><li> URL: <a href="http://creativecommons.org/publicdomain/zero/1.0/legalcode">http://creativecommons.org/publicdomain/zero/1.0/legalcode</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:90dc5c0be029de84e523b9b3922520e79e0e6f08&dn=cc0.txt</code>’
</li></ul>
</li><li> Eclipse Public License 1.0
<ul>
<li> Identifier: ‘<samp>EPL-1.0</samp>’
</li><li> URL: <a href="http://www.eclipse.org/legal/epl-v10.html">http://www.eclipse.org/legal/epl-v10.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:4c6a2ad0018cd461e9b0fc44e1b340d2c1828b22&dn=epl-1.0.txt</code>’
</li></ul>
</li><li> Expat License (sometimes called the MIT license)
<ul>
<li> Identifier: ‘<samp>Expat</samp>’
</li><li> URL: <a href="http://www.jclark.com/xml/copying.txt">http://www.jclark.com/xml/copying.txt</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&dn=expat.txt</code>’
</li></ul>
</li><li> FreeBSD License
<ul>
<li> URL: <a href="http://www.freebsd.org/copyright/freebsd-license.html">http://www.freebsd.org/copyright/freebsd-license.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:87f119ba0b429ba17a44b4bffcab33165ebdacc0&dn=freebsd.txt</code>’
</li></ul>
</li><li> GNU General Public License (GPL) version 2
<ul>
<li> Identifier: ‘<samp>GNU-GPL-2.0</samp>’
</li><li> URL: <a href="http://www.gnu.org/licenses/gpl-2.0.html">http://www.gnu.org/licenses/gpl-2.0.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:cf05388f2679ee054f2beb29a391d25f4e673ac3&dn=gpl-2.0.txt</code>’
</li></ul>
</li><li> GNU General Public License (GPL) version 3
<ul>
<li> Identifier: ‘<samp>GNU-GPL-3.0</samp>’
</li><li> URL: <a href="http://www.gnu.org/licenses/gpl-3.0.html">http://www.gnu.org/licenses/gpl-3.0.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:1f739d935676111cfff4b4693e3816e664797050&dn=gpl-3.0.txt</code>’
</li></ul>
</li><li> GNU Lesser General Public License, version 2.1
<ul>
<li> Identifier: ‘<samp>GNU-LGPL-2.1</samp>’
</li><li> URL: <a href="http://www.gnu.org/licenses/lgpl-2.1.html">http://www.gnu.org/licenses/lgpl-2.1.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:5de60da917303dbfad4f93fb1b985ced5a89eac2&dn=lgpl-2.1.txt</code>’
</li></ul>
</li><li> GNU Lesser General Public License, version 3
<ul>
<li> Identifier: ‘<samp>GNU-LGPL-3.0</samp>’
</li><li> URL: <a href="http://www.gnu.org/licenses/lgpl-3.0.html">http://www.gnu.org/licenses/lgpl-3.0.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:0ef1b8170b3b615170ff270def6427c317705f85&dn=lgpl-3.0.txt</code>’
</li></ul>
</li><li> GNU Affero General Public License, version 3
<ul>
<li> Identifier: ‘<samp>GNU-AGPL-3.0</samp>’
</li><li> URL: <a href="http://www.gnu.org/licenses/agpl-3.0.html">http://www.gnu.org/licenses/agpl-3.0.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt</code>’
</li></ul>
</li><li> The ISC License
<ul>
<li> URL: <a href="https://www.isc.org/downloads/software-support-policy/isc-license/">https://www.isc.org/downloads/software-support-policy/isc-license/</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:b8999bbaf509c08d127678643c515b9ab0836bae&dn=ISC.txt</code>’
</li></ul>
</li><li> Mozilla Public License 2.0
<ul>
<li> Identifier: ‘<samp>MPL-2.0</samp>’
</li><li> URL: <a href="http://www.mozilla.org/MPL/2.0">http://www.mozilla.org/MPL/2.0</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:3877d6d54b3accd4bc32f8a48bf32ebc0901502a&dn=mpl-2.0.txt</code>’
</li></ul>
</li><li> Public Domain
<ul>
<li> Public domain is not a license (see
<a href="https://www.gnu.org/licenses/license-list.html#PublicDomain">https://www.gnu.org/licenses/license-list.html#PublicDomain</a>). If
you want to release your work to the public domain, the FSF recommends
using CC0.
</li><li> Magnet Link: ‘<code>magnet:?xt=urn:btih:e95b018ef3580986a04669f1b5879592219e2a7a&dn=public-domain.txt</code>’
</li></ul>
</li><li> WTFPL
<ul>
<li> Identifier: ‘<samp>WTFPL</samp>’
</li><li> URL: <a href="http://www.wtfpl.net/txt/copying/">http://www.wtfpl.net/txt/copying/</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:723febf9f6185544f57f0660a41489c7d6b4931b&dn=wtfpl.txt</code>’
</li></ul>
</li><li> X11 License
<ul>
<li> URL: <a href="http://www.xfree86.org/3.3.6/COPYRIGHT2.html#3">http://www.xfree86.org/3.3.6/COPYRIGHT2.html#3</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:5305d91886084f776adcf57509a648432709a7c7&dn=x11.txt</code>’
</li></ul>
</li><li> XFree86 License
<ul>
<li> Identifier: ‘<samp>Modified-BSD</samp>’
</li><li> URLs:
<a href="http://www.xfree86.org/3.3.6/COPYRIGHT2.html#3">http://www.xfree86.org/3.3.6/COPYRIGHT2.html#3</a>
<a href="http://www.xfree86.org/current/LICENSE4.html">http://www.xfree86.org/current/LICENSE4.html</a>
</li><li> Magnet link: ‘<code>magnet:?xt=urn:btih:12f2ec9e8de2a3b0002a33d518d6010cc8ab2ae9&dn=xfree86.txt</code>’
</li></ul>
</li></ul>
<a name="Undetected-Free-Licenses"></a>
<h3 class="section">6.2 Undetected Free Licenses</h3>
<p>If you are using a free license that isn’t detected by LibreJS and isn’t
listed in the previous section, please send a message to
<a href="mailto:bug-librejs@gnu.org">bug-librejs@gnu.org</a> regarding this license, where code released under
this license can be found, and where to find the license text and
information.
</p>
<p>Many free licenses are listed in this page:
<a href="http://www.gnu.org/licenses/license-list.html">http://www.gnu.org/licenses/license-list.html</a>
</p>
<hr>
<a name="Setting-Your-JavaScript-Free"></a>
<div class="header">
<p>
Next: <a href="#Installation-Requirements" accesskey="n" rel="next">Installation Requirements</a>, Previous: <a href="#Free-Licenses-Detection" accesskey="p" rel="prev">Free Licenses Detection</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Setting-Your-JavaScript-Free-1"></a>
<h2 class="chapter">7 Setting Your JavaScript Free</h2>
<p>The first step is releasing your JavaScript under a free license. If
you are already using a free library, or you’re not using any
third-party libraries, it might only take a few minutes.
</p>
<p>All JavaScript code on a web page (inline, on-page, and external) shares
a common scope. Thus, code is generally either rejected or accepted as a
whole by LibreJS. If some JavaScript code is found to be nontrivial and
nonfree, then most of the time, all the the rest is discarded as well.
</p>
<p>On your website, take a look at your HTML source. You can identify
distinct pieces of JavaScript that might be free and some other that are
nonfree.
</p>
<p><em>Tip</em>: By running LibreJS on your page, you will get a list of all the
JavaScript that was blocked. This gives you an overview of the
JavaScript in your page.
</p>
<p>Imagine a page that contains several pieces of JavaScript from various
sources:
</p><ul>
<li> On top, within the <code><head></code> tag, it includes jQuery
</li><li> Then, some JavaScript code that you have written
</li><li> At the bottom, a JavaScript-based Facebook widget
</li><li> Also, there’s some analytics tracking code
</li></ul>
<dl compact="compact">
<dt><em>JavaScript that is already free</em></dt>
<dd><p>First, you must ensure that the library is free. If the file contains
a copyright and a license notice, you won’t need to look any further.
But if there’s no mention of the license, or if it’s too brief, you’ll
have to look for a COPYING or LICENSE file within the original library’s
source package, or on the library’s official website.
</p>
</dd>
<dt><em>Your own JavaScript</em></dt>
<dd><p>The free license given to your code should be compatible with the rest
of the JavaScript on a page. A good way to check is to read up on
them: <a href="http://www.gnu.org/licenses/license-list.html">http://www.gnu.org/licenses/license-list.html</a>
</p>
</dd>
<dt><em>Nonfree JavaScript</em></dt>
<dd><p>This might be the case with an analytics tracker, social media
widgets, and code that runs ads. Removing these pieces of code from your
site is required to have the rest accepted as free. There are
often alternatives to nonfree libraries or to third-party services:
</p>
<ul>
<li> If you have used nonfree third-party code as the base to write your own
code, try to find a free alternative.
</li><li> If you’re using a third-party service such as an analytics service,
replace it with a free alternative like Piwik.
</li><li> If you can’t find free JavaScript that has already been developed,
write it yourself! Who knows, your own solution might be the start of
a brilliant project!
</li></ul>
</dd>
</dl>
<a name="JavaScript-Web-Labels"></a>
<h3 class="section">7.1 JavaScript Web Labels</h3>
<p>One way to make your website work with LibreJS is by defining a
JavaScript Web Labels table.
</p>
<p>A JavaScript Web Labels table is informative to both site visitors and
the LibreJS program. You make a Web Labels table on a new HTML page
that’s linked to from your main page. The table lists each of your
site’s JavaScript files, that file’s corresponding human-readable source
file, and the canonical url of its free license.
</p>
<p>When using a JavaScript Web Labels table for your own files, it’s
important to put a copying permission statement at the top of each source
file listed in right-most column of the Web Labels table. For info on how
properly release your code as free software, see
<a href="https://www.gnu.org/licenses/gpl-howto.html">https://www.gnu.org/licenses/gpl-howto.html</a>. Future versions of
LibreJS will require a copying permission statement or other license
notice for source files listed in a Web Labels table.
</p>
<p>More information on JavaScript Web Labels is detailed here:
<a href="https://www.gnu.org/software/librejs/free-your-javascript.html#step3">https://www.gnu.org/software/librejs/free-your-javascript.html#step3</a>
and here:
<a href="https://www.gnu.org/licenses/javascript-labels.html">https://www.gnu.org/licenses/javascript-labels.html</a>.
</p>
<a name="Specifying-multiple-licenses-for-a-single-JavaScript-file"></a>
<h4 class="subsection">7.1.1 Specifying multiple licenses for a single JavaScript file</h4>
<p>If you compile or concatenate your JavaScript into a single file, the
source files you’re combining may be released under different licenses.
You can specify multiple licenses for the file in a JavaScript Web Labels
table, like this:
</p>
<pre class="verbatim"><table id="jslicense-labels1">
<tr>
<td><a href="all.min.js">all.min.js</a></td>
<td>
<a href="http://www.gnu.org/licenses/gpl-3.0.html"
>GNU-GPL-3.0-or-later</a>
<br />
<a href="http://www.apache.org/licenses/LICENSE-2.0"
>Apache-2.0</a>
</td>
<td>
<a href="gpl-script.js">gpl-script.js</a>
<br />
<a href="apache-script.js">apache-script.js</a>
</td>
</tr>
</table>
</pre>
<p>The <code><br /></code> tags just make the table more understandable when
looking at the rendered version of it on the license page. They aren’t
required by LibreJS.
</p>
<p>If all the licenses contained in the second column are recognized by
LibreJS to be free licenses, then LibreJS will allow the file in the
first column to be run.
</p>
<a name="Adding-a-stylized-comment-in-your-JavaScript-files-and-on-your-page"></a>
<h3 class="section">7.2 Adding a stylized comment in your JavaScript files and on your page</h3>
<p>See a “Convention for releasing free JavaScript programs” in the
JavaScript Trap <a href="http://www.gnu.org/philosophy/javascript-trap.html">http://www.gnu.org/philosophy/javascript-trap.html</a>
</p>
<p>Adding this notice will ensure LibreJS will find the JavaScript file to
be free. The <code>@licstart</code> and <code>@licend</code> lines at the
beginning and end of the stylized comment are necessary to make a clear
statement that the _entire code_ in the file is free. This means that
you must ensure that no nonfree code was carelessly appended at the end
of the file.
</p>
<p>In the main HTML page, the license notice covers JavaScript contained
in all <code><script></code> tags with on-page code and the inline
JavaScript (in event attributes such as onload, onclick, etc, …).
Since external files have their own stylized comment, they are
not covered by the notice in the main HTML page. Make sure to identify
all the licenses available. LibreJS will only ensure it matches a
notice of an allowed license once, so the order does not matter, but
the responsibility is on you to make sure all code is under the free
licenses mentioned between <code>@licstart</code> and <code>@licend</code>.
</p>
<p>You should make <em>only</em> one <code>@licstart</code> <code>@licend</code>
comment in your page, since it pertains to the entire code on page
across all <code><script></code> tags and inline html attributes.
</p>
<p>When you use the JavaScript Web Labels method, you should still include a
license notice at the top of each of your source files. This ensures that
if someone copies the file and uses it for something else, the license
remains intact.
</p>
<p>For more info on making your JavaScript LibreJS-compliant, see this web
page: <a href="https://www.gnu.org/software/librejs/free-your-javascript.html">https://www.gnu.org/software/librejs/free-your-javascript.html</a>
</p>
<hr>
<a name="Installation-Requirements"></a>
<div class="header">
<p>
Next: <a href="#LibreJS-Internals" accesskey="n" rel="next">LibreJS Internals</a>, Previous: <a href="#Setting-Your-JavaScript-Free" accesskey="p" rel="prev">Setting Your JavaScript Free</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Installation-Requirements-1"></a>
<h2 class="appendix">Appendix A Installation Requirements</h2>
<a name="Mozilla-Browser"></a>
<h3 class="appendixsec">A.1 Mozilla Browser</h3>
<p>You will need one of the many flavors of the Mozilla browser to use
LibreJS. It can be installed on the following:
</p>
<p>GNU IceCat, Mozilla Firefox, Trisquel Abrowser, Debian Iceweasel.
</p>
<p>LibreJS works on these browsers starting from version 29. We
recommend that you use the latest version of your Mozilla browser.
LibreJS has been tested extensively on multiple GNU/Linux distributions,
but it is compatible any operating system as long as you’re using a
compatible Mozilla browser.
</p>
<a name="Mozilla_0027s-Add_002don-SDK"></a>
<h3 class="appendixsec">A.2 Mozilla’s Add-on SDK</h3>
<p>LibreJS uses the Mozilla Add-on SDK (Software Development Kit), a
set of APIs and tools to create add-ons for Mozilla browsers.
</p>
<p>You do not need the Add-on SDK to use LibreJS xpi file or to install it
using the packaged version, but it is required in order to package the
LibreJS source code into an xpi file using <code>make</code>. If you would like
to run the tests for LibreJS or make changes to the source files, you
will need the Add-on SDK as well. For the “make” command to work
properly, you must have the <code>cfx</code> command available on your system
from the command line.
</p>
<p>The latest tarball for the Add-on SDK is available at:
</p>
<p><a href="https://ftp.mozilla.org/pub/mozilla.org/labs/jetpack/jetpack-sdk-latest.tar.gz">https://ftp.mozilla.org/pub/mozilla.org/labs/jetpack/jetpack-sdk-latest.tar.gz</a>
</p>
<p>Instructions on how to get it working are available here:
</p>
<p><a href="https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/tutorials/installation.html">https://addons.mozilla.org/en-US/developers/docs/sdk/latest/dev-guide/tutorials/installation.html</a>
</p>
<p>In order to use <code>make</code> with LibreJS source, however, it is ideal to
have <code>cfx</code> available at all times and for all users.
</p>
<p>An easy way to do this is to extract the contents of the tarball and to
place the files inside <samp>/usr/lib/addon-sdk</samp> and then creating a
symbolic link in <samp>/usr/bin</samp>, as follows:
</p>
<div class="example">
<pre class="example">sudo ln -s /usr/lib/addon-sdk/bin/cfx /usr/bin/cfx
</pre></div>
<p>The <code>cfx</code> command will then be available to all users.
</p>
<p>The Add-on SDK is released under the Mozilla Public License 2.0.
</p>
<hr>
<a name="LibreJS-Internals"></a>
<div class="header">
<p>
Next: <a href="#Tests" accesskey="n" rel="next">Tests</a>, Previous: <a href="#Installation-Requirements" accesskey="p" rel="prev">Installation Requirements</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="LibreJS-Internals-1"></a>
<h2 class="appendix">Appendix B LibreJS Internals</h2>
<p>LibreJS intercepts HTTP responses and rewrites their contents after
analyzing JavaScript within them. It does not remove script nodes and
attributes from the page, but instead “deactivates” them by modifying
the <code>type</code> and <code>src</code> attributes on script elements and by
moving the contents of inline JavaScript attributes such as onClick
into harmless attributes.
</p>
<p>LibreJS detects the most common cases using the HTTP response method
described above, but in extremely rare cases, or when running code
locally, LibreJS cannot detect JavaScript during the response stage.
</p>
<p>To remedy this issue, and as a final safeguard, LibreJS takes a look
at the scripts that are about to be executed while the browser engine is
parsing the page. If the script is not found in a list of accepted
scripts populated earlier, the execution will be prevented. This is to
ensure content types that are not regular HTML (binhex with HTML in it,
…) and JavaScript do not fall through the cracks and get executed.
</p>
<hr>
<a name="Tests"></a>
<div class="header">
<p>
Next: <a href="#GNU-Free-Documentation-License" accesskey="n" rel="next">GNU Free Documentation License</a>, Previous: <a href="#LibreJS-Internals" accesskey="p" rel="prev">LibreJS Internals</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="Tests-1"></a>
<h2 class="appendix">Appendix C Tests</h2>
<p>In order to better understand how LibreJS works, you can try to visit
these pages with LibreJS installed and enabled and see how they are
being processed:
</p>
<ul>
<li> <a href="http://lduros.net/assets/librejs/tests/trivial-inline-trivial-external/">http://lduros.net/assets/librejs/tests/trivial-inline-trivial-external/</a>
This page contains trivial on-page JavaScript code, and an external
script that contains trivial JavaScript code. Therefore, all JavaScript
is being executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/trivial-inline-nontrivial-external/">http://lduros.net/assets/librejs/tests/trivial-inline-nontrivial-external/</a>
The on-page script here is trivial and uses a built-in method, but the
external script in this page is nontrivial (defines a function.) The
external script is blocked, the inline script is executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/nontrivial-inline-trivial-external/">http://lduros.net/assets/librejs/tests/nontrivial-inline-trivial-external/</a>
This page contains nontrivial code on page, and trivial code in its
external page. All JavaScript is <em>removed</em> from the page, and the
external script is never analyzed, since the nontrivial conditions are
already met in the page.
</li><li> <a href="http://lduros.net/assets/librejs/tests/free-inline-free-external/">http://lduros.net/assets/librejs/tests/free-inline-free-external/</a>
This page contains free on-page (GPL 3) JavaScript, and free external
Javascript. Therefore all JavaScript is being executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/free-inline-nonfree-nontrivial-external/">http://lduros.net/assets/librejs/tests/free-inline-nonfree-nontrivial-external/</a>
This page contains free on-page JavaScript. The external script contains
nonfree nontrivial JavaScript (AJAX request). The free code that is
inline is executed, but the external file is blocked.
</li><li> <a href="http://lduros.net/assets/librejs/tests/intrinsec-event/">http://lduros.net/assets/librejs/tests/intrinsec-event/</a> This page
contains trivial on-page code, with an intrinsic event in an html
attribute (onload). All JavaScript is being executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/trivial-inline-free-external-defines-function/">http://lduros.net/assets/librejs/tests/trivial-inline-free-external-defines-function/</a>
This page contains on-page trivial JavaScript (only makes a window alert
and loads an external script using the html <script> tag with the src
attribute. The external script is free (GPL v3), and since it is only
nontrivial because it defines a function, the on-page trivial code is
allowed to use it. All JavaScript is being executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/trivial-inline-free-external-writes-script/">http://lduros.net/assets/librejs/tests/trivial-inline-free-external-writes-script/</a>
This page contains trivial on-page JavaScript code, and loads an
external script that is free. Since no function is defined, the external
script is being analyzed. The external script is free. Trivial here is
not allowed because the external script, although free, writes a
script. The inline trivial script should also have a free license notice
for it to be interpreted.
</li><li> <a href="http://lduros.net/assets/librejs/tests/shelltypist/demo/real-life-example-with-jquery-free.html">http://lduros.net/assets/librejs/tests/shelltypist/demo/real-life-example-with-jquery-free.html</a>
This is a real-life example of a small jQuery plugin. The on-page
JavaScript code has a free license. The jQuery external file has a free
licensed. The shelltypist.js file has a free license as well. All
licenses are defined between <code>@licstart</code> and <code>@licend</code>. All
JavaScript is executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/shelltypist/demo/same-page-without-free-license.html">http://lduros.net/assets/librejs/tests/shelltypist/demo/same-page-without-free-license.html</a>
This is the same page than the previous example, except it does not have
a free license for the main HTML page on-page script. While the actual
code there is trivial, since jQuery defines methods that make use of
AJAX, trivial code is not allowed, and no JavaScript is executed.
</li><li> <a href="http://lduros.net/assets/librejs/tests/test-labels/">http://lduros.net/assets/librejs/tests/test-labels/</a> This page
contains JavaScript (jQuery minified) that does not have proper license
information in the file, as it has no <code>@licstart</code> <code>@licend</code>
comment. It would be considered nonfree, however, the page itself uses
the JavaScript Web Labels method. On the page itself, you will find a
link labeled “JavaScript License Information”, which leads to a page
that contains a properly formatted table with the required data on the
external JavaScript file. LibreJS visits this link and determines the
version of jQuery linked from the original page is the one listed there,
and flags it as free. All JavaScript is executed (and the title should
turn green.)
</li></ul>
<hr>
<a name="GNU-Free-Documentation-License"></a>
<div class="header">
<p>
Previous: <a href="#Tests" accesskey="p" rel="prev">Tests</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p>
</div>
<a name="GNU-Free-Documentation-License-1"></a>
<h2 class="appendix">Appendix D GNU Free Documentation License</h2>
<div align="center">Version 1.3, 3 November 2008
</div>
<div class="display">
<pre class="display">Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<a href="http://fsf.org/">http://fsf.org/</a>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
</pre></div>
<ol>
<li> PREAMBLE
<p>The purpose of this License is to make a manual, textbook, or other
functional and useful document <em>free</em> in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or noncommercially.
Secondarily, this License preserves for the author and publisher a way
to get credit for their work, while not being considered responsible
for modifications made by others.
</p>
<p>This License is a kind of “copyleft”, which means that derivative
works of the document must themselves be free in the same sense. It
complements the GNU General Public License, which is a copyleft
license designed for free software.
</p>
<p>We have designed this License in order to use it for manuals for free
software, because free software needs free documentation: a free
program should come with manuals providing the same freedoms that the
software does. But this License is not limited to software manuals;
it can be used for any textual work, regardless of subject matter or
whether it is published as a printed book. We recommend this License
principally for works whose purpose is instruction or reference.
</p>
</li><li> APPLICABILITY AND DEFINITIONS
<p>This License applies to any manual or other work, in any medium, that
contains a notice placed by the copyright holder saying it can be
distributed under the terms of this License. Such a notice grants a
world-wide, royalty-free license, unlimited in duration, to use that
work under the conditions stated herein. The “Document”, below,
refers to any such manual or work. Any member of the public is a
licensee, and is addressed as “you”. You accept the license if you
copy, modify or distribute the work in a way requiring permission
under copyright law.
</p>
<p>A “Modified Version” of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
</p>
<p>A “Secondary Section” is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document’s overall
subject (or to related matters) and contains nothing that could fall
directly within that overall subject. (Thus, if the Document is in
part a textbook of mathematics, a Secondary Section may not explain
any mathematics.) The relationship could be a matter of historical
connection with the subject or with related matters, or of legal,
commercial, philosophical, ethical or political position regarding
them.
</p>
<p>The “Invariant Sections” are certain Secondary Sections whose titles
are designated, as being those of Invariant Sections, in the notice
that says that the Document is released under this License. If a
section does not fit the above definition of Secondary then it is not
allowed to be designated as Invariant. The Document may contain zero
Invariant Sections. If the Document does not identify any Invariant
Sections then there are none.
</p>
<p>The “Cover Texts” are certain short passages of text that are listed,
as Front-Cover Texts or Back-Cover Texts, in the notice that says that
the Document is released under this License. A Front-Cover Text may
be at most 5 words, and a Back-Cover Text may be at most 25 words.
</p>
<p>A “Transparent” copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed of
pixels) generic paint programs or (for drawings) some widely available
drawing editor, and that is suitable for input to text formatters or
for automatic translation to a variety of formats suitable for input
to text formatters. A copy made in an otherwise Transparent file
format whose markup, or absence of markup, has been arranged to thwart
or discourage subsequent modification by readers is not Transparent.
An image format is not Transparent if used for any substantial amount
of text. A copy that is not “Transparent” is called “Opaque”.
</p>
<p>Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input
format, SGML or XML using a publicly available
DTD, and standard-conforming simple HTML,
PostScript or PDF designed for human modification. Examples
of transparent image formats include PNG, XCF and
JPG. Opaque formats include proprietary formats that can be
read and edited only by proprietary word processors, SGML or
XML for which the DTD and/or processing tools are
not generally available, and the machine-generated HTML,
PostScript or PDF produced by some word processors for
output purposes only.
</p>
<p>The “Title Page” means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the material
this License requires to appear in the title page. For works in
formats which do not have any title page as such, “Title Page” means
the text near the most prominent appearance of the work’s title,
preceding the beginning of the body of the text.
</p>
<p>The “publisher” means any person or entity that distributes copies
of the Document to the public.
</p>
<p>A section “Entitled XYZ” means a named subunit of the Document whose
title either is precisely XYZ or contains XYZ in parentheses following
text that translates XYZ in another language. (Here XYZ stands for a
specific section name mentioned below, such as “Acknowledgements”,
“Dedications”, “Endorsements”, or “History”.) To “Preserve the Title”
of such a section when you modify the Document means that it remains a
section “Entitled XYZ” according to this definition.
</p>
<p>The Document may include Warranty Disclaimers next to the notice which
states that this License applies to the Document. These Warranty
Disclaimers are considered to be included by reference in this
License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and has
no effect on the meaning of this License.
</p>
</li><li> VERBATIM COPYING
<p>You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License applies
to the Document are reproduced in all copies, and that you add no other
conditions whatsoever to those of this License. You may not use
technical measures to obstruct or control the reading or further
copying of the copies you make or distribute. However, you may accept
compensation in exchange for copies. If you distribute a large enough
number of copies you must also follow the conditions in section 3.
</p>
<p>You may also lend copies, under the same conditions stated above, and
you may publicly display copies.
</p>
</li><li> COPYING IN QUANTITY
<p>If you publish printed copies (or copies in media that commonly have
printed covers) of the Document, numbering more than 100, and the
Document’s license notice requires Cover Texts, you must enclose the
copies in covers that carry, clearly and legibly, all these Cover
Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
the back cover. Both covers must also clearly and legibly identify
you as the publisher of these copies. The front cover must present
the full title with all words of the title equally prominent and
visible. You may add other material on the covers in addition.
Copying with changes limited to the covers, as long as they preserve
the title of the Document and satisfy these conditions, can be treated
as verbatim copying in other respects.
</p>
<p>If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto adjacent
pages.
</p>
<p>If you publish or distribute Opaque copies of the Document numbering
more than 100, you must either include a machine-readable Transparent
copy along with each Opaque copy, or state in or with each Opaque copy
a computer-network location from which the general network-using
public has access to download using public-standard network protocols
a complete Transparent copy of the Document, free of added material.
If you use the latter option, you must take reasonably prudent steps,
when you begin distribution of Opaque copies in quantity, to ensure
that this Transparent copy will remain thus accessible at the stated
location until at least one year after the last time you distribute an
Opaque copy (directly or through your agents or retailers) of that
edition to the public.
</p>
<p>It is requested, but not required, that you contact the authors of the
Document well before redistributing any large number of copies, to give
them a chance to provide you with an updated version of the Document.
</p>
</li><li> MODIFICATIONS
<p>You may copy and distribute a Modified Version of the Document under
the conditions of sections 2 and 3 above, provided that you release
the Modified Version under precisely this License, with the Modified
Version filling the role of the Document, thus licensing distribution
and modification of the Modified Version to whoever possesses a copy
of it. In addition, you must do these things in the Modified Version:
</p>
<ol>
<li> Use in the Title Page (and on the covers, if any) a title distinct
from that of the Document, and from those of previous versions
(which should, if there were any, be listed in the History section
of the Document). You may use the same title as a previous version
if the original publisher of that version gives permission.
</li><li> List on the Title Page, as authors, one or more persons or entities
responsible for authorship of the modifications in the Modified
Version, together with at least five of the principal authors of the
Document (all of its principal authors, if it has fewer than five),
unless they release you from this requirement.
</li><li> State on the Title page the name of the publisher of the
Modified Version, as the publisher.
</li><li> Preserve all the copyright notices of the Document.
</li><li> Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
</li><li> Include, immediately after the copyright notices, a license notice
giving the public permission to use the Modified Version under the
terms of this License, in the form shown in the Addendum below.
</li><li> Preserve in that license notice the full lists of Invariant Sections
and required Cover Texts given in the Document’s license notice.
</li><li> Include an unaltered copy of this License.
</li><li> Preserve the section Entitled “History”, Preserve its Title, and add
to it an item stating at least the title, year, new authors, and
publisher of the Modified Version as given on the Title Page. If
there is no section Entitled “History” in the Document, create one
stating the title, year, authors, and publisher of the Document as
given on its Title Page, then add an item describing the Modified
Version as stated in the previous sentence.
</li><li> Preserve the network location, if any, given in the Document for
public access to a Transparent copy of the Document, and likewise
the network locations given in the Document for previous versions
it was based on. These may be placed in the “History” section.
You may omit a network location for a work that was published at
least four years before the Document itself, or if the original
publisher of the version it refers to gives permission.
</li><li> For any section Entitled “Acknowledgements” or “Dedications”, Preserve
the Title of the section, and preserve in the section all the
substance and tone of each of the contributor acknowledgements and/or
dedications given therein.
</li><li> Preserve all the Invariant Sections of the Document,
unaltered in their text and in their titles. Section numbers
or the equivalent are not considered part of the section titles.
</li><li> Delete any section Entitled “Endorsements”. Such a section
may not be included in the Modified Version.
</li><li> Do not retitle any existing section to be Entitled “Endorsements” or
to conflict in title with any Invariant Section.
</li><li> Preserve any Warranty Disclaimers.
</li></ol>
<p>If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no material
copied from the Document, you may at your option designate some or all
of these sections as invariant. To do this, add their titles to the
list of Invariant Sections in the Modified Version’s license notice.
These titles must be distinct from any other section titles.
</p>
<p>You may add a section Entitled “Endorsements”, provided it contains
nothing but endorsements of your Modified Version by various
parties—for example, statements of peer review or that the text has
been approved by an organization as the authoritative definition of a
standard.
</p>
<p>You may add a passage of up to five words as a Front-Cover Text, and a
passage of up to 25 words as a Back-Cover Text, to the end of the list
of Cover Texts in the Modified Version. Only one passage of
Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document already
includes a cover text for the same cover, previously added by you or
by arrangement made by the same entity you are acting on behalf of,
you may not add another; but you may replace the old one, on explicit
permission from the previous publisher that added the old one.
</p>
<p>The author(s) and publisher(s) of the Document do not by this License
give permission to use their names for publicity for or to assert or
imply endorsement of any Modified Version.
</p>
</li><li> COMBINING DOCUMENTS
<p>You may combine the Document with other documents released under this
License, under the terms defined in section 4 above for modified
versions, provided that you include in the combination all of the
Invariant Sections of all of the original documents, unmodified, and
list them all as Invariant Sections of your combined work in its
license notice, and that you preserve all their Warranty Disclaimers.
</p>
<p>The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name but
different contents, make the title of each such section unique by
adding at the end of it, in parentheses, the name of the original
author or publisher of that section if known, or else a unique number.
Make the same adjustment to the section titles in the list of
Invariant Sections in the license notice of the combined work.
</p>
<p>In the combination, you must combine any sections Entitled “History”
in the various original documents, forming one section Entitled
“History”; likewise combine any sections Entitled “Acknowledgements”,
and any sections Entitled “Dedications”. You must delete all
sections Entitled “Endorsements.”
</p>
</li><li> COLLECTIONS OF DOCUMENTS
<p>You may make a collection consisting of the Document and other documents
released under this License, and replace the individual copies of this
License in the various documents with a single copy that is included in
the collection, provided that you follow the rules of this License for
verbatim copying of each of the documents in all other respects.
</p>
<p>You may extract a single document from such a collection, and distribute
it individually under this License, provided you insert a copy of this
License into the extracted document, and follow this License in all
other respects regarding verbatim copying of that document.
</p>
</li><li> AGGREGATION WITH INDEPENDENT WORKS
<p>A compilation of the Document or its derivatives with other separate
and independent documents or works, in or on a volume of a storage or
distribution medium, is called an “aggregate” if the copyright
resulting from the compilation is not used to limit the legal rights
of the compilation’s users beyond what the individual works permit.
When the Document is included in an aggregate, this License does not
apply to the other works in the aggregate which are not themselves
derivative works of the Document.
</p>
<p>If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half of
the entire aggregate, the Document’s Cover Texts may be placed on
covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic form.
Otherwise they must appear on printed covers that bracket the whole
aggregate.
</p>
</li><li> TRANSLATION
<p>Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section 4.
Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also include
the original English version of this License and the original versions
of those notices and disclaimers. In case of a disagreement between
the translation and the original version of this License or a notice
or disclaimer, the original version will prevail.
</p>
<p>If a section in the Document is Entitled “Acknowledgements”,
“Dedications”, or “History”, the requirement (section 4) to Preserve
its Title (section 1) will typically require changing the actual
title.
</p>
</li><li> TERMINATION
<p>You may not copy, modify, sublicense, or distribute the Document
except as expressly provided under this License. Any attempt
otherwise to copy, modify, sublicense, or distribute it is void, and
will automatically terminate your rights under this License.
</p>
<p>However, if you cease all violation of this License, then your license
from a particular copyright holder is reinstated (a) provisionally,
unless and until the copyright holder explicitly and finally
terminates your license, and (b) permanently, if the copyright holder
fails to notify you of the violation by some reasonable means prior to
60 days after the cessation.
</p>
<p>Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.
</p>
<p>Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License. If your rights have been terminated and not permanently
reinstated, receipt of a copy of some or all of the same material does
not give you any rights to use it.
</p>
</li><li> FUTURE REVISIONS OF THIS LICENSE
<p>The Free Software Foundation may publish new, revised versions
of the GNU Free Documentation License from time to time. Such new
versions will be similar in spirit to the present version, but may
differ in detail to address new problems or concerns. See
<a href="http://www.gnu.org/copyleft/">http://www.gnu.org/copyleft/</a>.
</p>
<p>Each version of the License is given a distinguishing version number.
If the Document specifies that a particular numbered version of this
License “or any later version” applies to it, you have the option of
following the terms and conditions either of that specified version or
of any later version that has been published (not as a draft) by the
Free Software Foundation. If the Document does not specify a version
number of this License, you may choose any version ever published (not
as a draft) by the Free Software Foundation. If the Document
specifies that a proxy can decide which future versions of this
License can be used, that proxy’s public statement of acceptance of a
version permanently authorizes you to choose that version for the
Document.
</p>
</li><li> RELICENSING
<p>“Massive Multiauthor Collaboration Site” (or “MMC Site”) means any
World Wide Web server that publishes copyrightable works and also
provides prominent facilities for anybody to edit those works. A
public wiki that anybody can edit is an example of such a server. A
“Massive Multiauthor Collaboration” (or “MMC”) contained in the
site means any set of copyrightable works thus published on the MMC
site.
</p>
<p>“CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0
license published by Creative Commons Corporation, a not-for-profit
corporation with a principal place of business in San Francisco,
California, as well as future copyleft versions of that license
published by that same organization.
</p>
<p>“Incorporate” means to publish or republish a Document, in whole or
in part, as part of another Document.
</p>
<p>An MMC is “eligible for relicensing” if it is licensed under this
License, and if all works that were first published under this License
somewhere other than this MMC, and subsequently incorporated in whole
or in part into the MMC, (1) had no cover texts or invariant sections,
and (2) were thus incorporated prior to November 1, 2008.
</p>
<p>The operator of an MMC Site may republish an MMC contained in the site
under CC-BY-SA on the same site at any time before August 1, 2009,
provided the MMC is eligible for relicensing.
</p>
</li></ol>
<a name="ADDENDUM_003a-How-to-use-this-License-for-your-documents"></a>
<h3 class="heading">ADDENDUM: How to use this License for your documents</h3>
<p>To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:
</p>
<div class="smallexample">
<pre class="smallexample"> Copyright (C) <var>year</var> <var>your name</var>.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
Texts. A copy of the license is included in the section entitled ``GNU
Free Documentation License''.
</pre></div>
<p>If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts,
replace the “with…Texts.” line with this:
</p>
<div class="smallexample">
<pre class="smallexample"> with the Invariant Sections being <var>list their titles</var>, with
the Front-Cover Texts being <var>list</var>, and with the Back-Cover Texts
being <var>list</var>.
</pre></div>
<p>If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.
</p>
<p>If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License,
to permit their use in free software.
</p>
<hr>
</body>
</html>
|
