I realize the names are confusing, but Firefox handles JavaScript internally; Firefox does not use the Java plugin to handle JavaScript.

Firefox's settings for JavaScript are described in this article: JavaScript settings and preferences for interactive web pages.

Some add-ons can change how JavaScript works in the browser, particularly the NoScript extension. Security software also can filter/tweak pages.

Is the problem limited to particular pages? You could post a URL to see whether a volunteer could offer any specific insight.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do not click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

This page (the Hungarian Internet Banking application of CIB Bank) is not working under FF15.0.1 Java 7u7, but working under Java 6u26:

  https://ibank.cib.hu/Applet2.html

Any ideas?

Thank you. I've posted a reply earlier, but it appears not to have gone thru. Here is an URL of a page: LFI Gallery - if one clicks on the small pic, a window/pop-up should open with a larger photo. It works in Chrome and IE.

cor-el, I will try your suggestion sometime later.

When I click the image on the LFI Gallery page, there is a pause and then a new window opens. The script command for this is very straightforward:

Step 1 - Clicking calls this function with three parameters (shortened for posting):

 MM_openBrWindow('url','imgnum','scrollbars=yes,toolbar=no,status=no,resizable=yes,width=1267,height=842')"

Step 2 - That function uses the standard method to open a new window, simply passing on the same 3 parameters:

window.open(theURL,winName,features);

This work for me with Firefox's pop-up blocker enabled. Is that possible that you have any additional third party pop-up blockers that might be preventing the new window from opening?

I initially thought that Adblock Plus and Adblock Plus Popup Addon could be the culprits. I checked that and they were not responsible. So at last I followed cor-el's advice. After an afternoon and part of an evening's work, I'm kind of embarassed. I still have version 2.8.9 of RightToClick and that was the culprit. I'll upgrade to 2.9.3 and see what happens. Thank you all for all the advice!