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diff --git a/doc/manual/html_node/JavaScript-Detection.html b/doc/manual/html_node/JavaScript-Detection.html new file mode 100644 index 0000000..1ce0f95 --- /dev/null +++ b/doc/manual/html_node/JavaScript-Detection.html @@ -0,0 +1,165 @@ +<!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 6.0.8.20150117, 17 January 2015), +a GNU IceCat extension to detect and block nonfree nontrivial +JavaScript on webpages. + +Copyright (C) 2011 2012 2014 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 6.0.8.20150117: JavaScript Detection</title> + +<meta name="description" content="GNU LibreJS 6.0.8.20150117: JavaScript Detection"> +<meta name="keywords" content="GNU LibreJS 6.0.8.20150117: JavaScript Detection"> +<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="index.html#Top" rel="start" title="Top"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="index.html#Top" rel="up" title="Top"> +<link href="Free-Licenses-Detection.html#Free-Licenses-Detection" rel="next" title="Free Licenses Detection"> +<link href="How-to-Use.html#How-to-Use" rel="prev" title="How to Use"> +<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"> +<a name="JavaScript-Detection"></a> +<div class="header"> +<p> +Next: <a href="Free-Licenses-Detection.html#Free-Licenses-Detection" accesskey="n" rel="next">Free Licenses Detection</a>, Previous: <a href="How-to-Use.html#How-to-Use" accesskey="p" rel="prev">How to Use</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p> +</div> +<hr> +<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> +<div class="header"> +<p> +Next: <a href="Free-Licenses-Detection.html#Free-Licenses-Detection" accesskey="n" rel="next">Free Licenses Detection</a>, Previous: <a href="How-to-Use.html#How-to-Use" accesskey="p" rel="prev">How to Use</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>]</p> +</div> + + + +</body> +</html> |