Shoutbox

Alright, I recently spotted this userJS (myoperacom-sigremover.js) for Opera on userjs.com.
Now, what it does is removing the users signatures when their usernames are inserted into the script.
My question would be if it is possible to modify this script or if not write a new one that works with msghelp.net
and as an extra task, a script that hides avatars.
I myself know almost nothing about JavaScript so I thought one of you could try this.