What in a GreaseMonkey script can cause Firefox to crash?

I have a relatively large script in GreaseMonkey and it seems to be crashing the browser after some time. It looks like it does its thing and then after a while Firefox just dies. Seems to me that this has to be connected with to my script. The page I'm modifying is google.com and I'm developing the script on Mac. What are the common causes for G开发者_StackOverflowM scripts crashing Firefox?

Look for

• memory leaks (do you add some information to an array which you keep around? Make sure you don't use global variables.)
• Endless loops (won't crash FF, though)
• There might be an interaction between your script and the one from Google. For example, Google Mail will send an AXAJ request every few seconds to look for new mail. If your script is triggered by that, that could cause problems.

Only bugs in firefox or one of its components (spidermonkey, gecko...)