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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 6.0.8.20150117</title> + +<meta name="description" content="GNU LibreJS 6.0.8.20150117"> +<meta name="keywords" content="GNU LibreJS 6.0.8.20150117"> +<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 6.0.8.20150117</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 6.0.8.20150117, 17 January 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> 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> 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> 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> 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> 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> 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> 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> 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> 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> X11 License +<ul> +<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><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> 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> 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> 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></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> |