GNU LibreJS 6.0.8.20150117: JavaScript Detection

From ada88090ead2c3b9d0804794c5f20f9b24d1c2b1 Mon Sep 17 00:00:00 2001 From: Nik Nyby Date: Sat, 17 Jan 2015 17:12:36 -0500 Subject: Import to new git repository The old repository was using almost 100mb of space because of all the unnecessary files in the history. So I've imported the code to a new git repository. Unfortunately the history isn't viewable from this repository anymore. To see what happened with LibreJS before 2015, see the old Bazaar repo here: http://bzr.savannah.gnu.org/lh/librejs/ --- doc/manual/html_node/JavaScript-Detection.html | 165 +++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 doc/manual/html_node/JavaScript-Detection.html (limited to 'doc/manual/html_node/JavaScript-Detection.html') 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 @@ + + + + + +GNU LibreJS 6.0.8.20150117: JavaScript Detection + + + + + + + + + + + + + + + + + + + + +

+ +

5 JavaScript Detection

+ + +

LibreJS considers JavaScript on a page nontrivial if any of the +following are true: + +
It makes an AJAX request or is loaded along with scripts that make +an AJAX request, + +
It loads external scripts dynamically or is loaded along with +scripts that do, + +
It defines functions or methods and either loads an external script +(from HTML) or is loaded as one, + +
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: +
- Using the eval function +
- Calling methods with the square bracket notation +
- Using any other construct than a string literal with certain methods +(Obj.write, Obj.createElement, …). +
+

+ +

In practice, the JavaScript code in your page may be found trivial by +LibreJS if, as a whole: +

It does not define functions and it does not load external scripts +(with the HTML src attribute in a <script> tag). + +
It does not make AJAX calls. + +
It does not load external scripts with dynamic constructs. + +
It does not use constructs that may be used to do any of the above in +a non-obvious way (use of the eval() method, use of square bracket +method calls, use of concatenation with certain constructs or method +calls, …). + +

+ +

However, in some instances, you may be required by LibreJS to add a +stylized comment to JavaScript code that may be otherwise trivial. +

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. +

For instance, if your page contains the following: +

<script src="jquery.js"></script>
+<script>
+$.doSomething();
+</script>
+

+ +

While $.doSomething(); 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. $.doSomething() 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. +

In practice also, the JavaScript code in an external file (an external +.js file loaded on your page) may be found trivial if it does not +define functions/methods. +

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. +

If your JavaScript code makes AJAX requests, it’s important to get an +accurate Content-Type in the response from the server. For +example, if you’re using JSON, set it to application/json. +This is because LibreJS alters the content of text/html +responses. +

+ + + + + + -- cgit v1.2.3