Ray Bell wrote:But I see little in the way of 'suggestions'... just an assumption that I know what to do when I see each magic word!
That instruction from Firefox says:
"To determine what script is running too long, open the Error Console (JavaScript Console prior to Firefox 2) and tell it to stop the script. The Error Console should identify the script causing the problem."
Take a step back. On that page, you see two possibilities: 1) It is something that happens on specific web pages, or 2) It is something that happens on many different web pages. From your description, it sounds like something that is happening with many different web pages. The suggestions in that section are to: 1) try uninstalling extensions to fix the problem, or 2) try creating a new profile. I would suggest the new profile. The original article contains a link that takes you to a full set of instructions for how to do that.