Sounds like the chase site is not compatable with FF4.

>I think I may have a virus on my computer. Firefox has been acting very wacky for the last two days. For a while it wouldn't respond at all when I clicked its icon in the system tray. Then I started getting this dialog when doing my online banking at chase.com. Specifically, clicking the date calendar icon in the Pay Bills section. Other sites seem unaffected.
>
>A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete.
>
>Script: chrome://tavgp/content/libs/include.js:595
>
>This started when I followed a prompt and installed the latest version of Firefox, so maybe it's FF itself and not a virus. I have uninstalled FF and reinstalled it and the same behavior continues. No other programs seem affected. I ran a virus scan (AVG) and it didn't find any problems.
>
>Any ideas?