Internet Explorer offers a way to change the JavaScript code at runtime using conditional comments (activated by a @cc_on
statement found in a comment).
Using this preprocessing feature decreases readability and maintainability, and can hinder automated tools. What's more, it is specific to Internet Explorer and won't work for other browsers.
The following code snippet illustrates the use of conditional comments:
/*@cc_on @if (@_jscript_version >= 5.5) document.write("You are using IE5.5 or newer"); @else document.write("You are using IE5 or older"); @end @*/