Heh, my school uses Moodle...
shaqywacky is right, you aren't actually asking anything, inject js into the browser? does moodle have any xss exploits? These can be found off google, and don't ask questions if they're going to be about potentially illegal activities. One more thing- until you can use the url bar for js injections, I suggest you don't use firebug.
-Quis custodiet ipsos custodes?, Juvenal