Hi, I've noticed the same issue . But for me this happens if I use Print Preview first. JavaScript works just fine before using Print Preview. But the most interesting thing is that when using javascript:window.close(); after Print Preview all that happens is that the character set of the page changes. On the other hand the character set works properly only after Print Preview. Interesting...

See Advanced Javascript Settings

If you have QuickJS installed, make sure it doesn't show a split icon if you encounter the problem.

Thanks. But I don't have that installed.

Try running Firefox in Diagnose Firefox issues using Troubleshoot Mode If it works correctly in that configuration, then one of your add-ons is the culprit.

You're a genius! I started FF4 in safe mode and it worked without a problem. I restarted and one by one disabled my add ons. It seems to be Google Toolbar for Firefox. When that is disabled the javascript works fine. Should I try to find a newer Google Toolbar for FF4? Thanks for your help.

It sounds like they need to update it to work with FF4.

There are some other extensions in the same flavour here which might provide an alternative: Google Toolbars

Oh, and can you click the "Helpful" button so that this post is flagged as solved please.

Thanks to Xircal for the tip, I got mine working again. I found out through trial and error that the addon that was giving me problems was the flashgot addon, which, after reflection, I'm happy to give up to get the close.window to work!

That's interesting. I'll make a note of that.

You could also consider posting your discovery on the Add-ons forums / AMO Feedback if you have time: https://forums.mozilla.org/addons/

Thanks for letting us know in any event.