FF4b - AJAX features don't work on most sites
AJAX stuff doesn't seem to work on a lot of sites. For example I can't get users' video lists on YouTube, the site just says it's loading endlessly.
Other sites like Google Reader are unusable because they rely on AJAX to fetch info every time you load the page. Everything works fine on other browsers though.
URL of affected sites
You can try to disable Firebug.
Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes). See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems
If it does work in Safe-mode then disable all your extensions and then try to find which is causing it by enabling one at a time until the problem reappears. You can use "Disable all add-ons" on the Diagnose Firefox issues using Troubleshoot Mode start window to disable all extensions. You have to close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")
Disabling Firebug fixed it, thanks. I only tried getting rid of the unsupported addons.
I disabled all add-ons except plugins but am still facing the problem. Should I disable plugins also? The site which I am trying to access is coded using atlas (ajax old name for visual studio 2005). The code runs perfectly fine with firefox older version (v3.0 and v3.5).