I'm not sure - it depends on what you didn't like about that
Basically, no matter what you do, you'll need to just hook into one of those document methods to call your javascript. I recommend you search the internet for 'pop up' 'javascript' and 'grey out' or something:
http://www.google.com/search?q=javas...ient=firefox-a
There are 128,000 hits. Hopefully one of them will do what you're looking for. If not, you may wish to hire a web programmer.