monline

Firefox has a built-in timeout for JavaScripts to prevent them from running too long. It is far from perfect (see this post for details on some possible problems), but better than nothing. You can set the timeout period in the dom.max_script_run_time preference (using the "about:config" URL), it's 10s in FF 2.x by default. You might need this if you're using lots of extensions, eg. web development stuff (Web Developer ext., Firebug, DOM Inspector, etc.). Some of these can trigger the timeout warning for web pages with larger DOMs, etc. Being a web developer, I see this warning a way too many times.