shajiindia,

IMHO, you should be doing something to fix the problem;

Why are you letting someone modify your live web-site?

Check the logs, close the exposure holes, etc. Then fix the code and don't let it happen again.

I've been hacked, and it isn't fun, but I fixed the source of the problem.

First, all of your JavaScript files should be read-only. Look at everything, since there may be other compromised files.

To answer your question, a very simple Perl script run every hour could check the modified JS to a checksum and if it fails to verify, then notify the sysadmin. But if the site is that un-secure, then maybe *they* could modify your Perl script!

Good Luck...Ed