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.

Most of the time, using those conditional comments can be easily avoided with some refactoring - using modern cross-browsers JavaScript frameworks and libraries. The following code snippet illustrates the use of conditional comments:

## Noncompliant Code Example

    /*@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
      @*/