I was working on a web development project. Until 30 minutes ago, I had discovered something strange with my code. It worked well on IE and Chrome but it created random results on Mozilla Firefox version 3.6.12. So i did some quick alert()s to find out whats went wrong. Surprisingly, I found out that if you pass a callback function that can accept parameter into setInterval. It will pass random numbers into the callback function when it wasn't suppose to. I tried to start Firefox in safe mode and run the test again. Unfortunately, the bug still exists.
If you're geeky enough to watch the bug live in action just head over the demo page to reproduce the bug.
Update #1: I just tested the code with setTimeout() it seems like setTimeout() is affected as well.
Update #2: I just filed a report at Bugzilla@Mozilla.
Update #3: It was my mistake. :P It isn't a bug but an inconsistency between browsers.