If you need to say this:
var myScriptTag = '</SCRIPT>';
Then you should do this:
var myScriptTag = '<' + '/SCRIPT' + '>';
which should hide the tag from the parser.
Another alternative is to escape the slash character with a backslash like this:
var myScriptTag = '<\/SCRIPT>';
Look at that previous line carefully, and see how the forward slash is preceeded by a backslash. After a long day cranking code out that might look like an upper case V, so it might be best to use the concatenation technique.