JavaScript 2.0-The Complete Reference, Second ... - freecodingtutorial

You must also indicate the comments containing conditional compilation statements by
beginning them with an @ directive and closing them with an @ symbol. For example:
/*@cc_on @*/
/*@set @debugging = true@*/
Because the processing of conditional compilation directives happens before normal script
interpretation, you can use it to selectively enable or disable pieces of code. Consider the
following script that defines one of two functions depending upon which version of JScript (if
any) is supported:
/*@cc_on @*/
/*@if (@_jscript_version >>= 5)
function doTask()
{
}
// some code using advanced IE5+ features
alert('IE Specific code!');
@else @*/
function doTask()
{
}
// some code using standard browser features
alert('Non-IE Specific code!');
/*@end @*/
doTask();