Jul 17 2009

firefox 3.5 fails – bug with ajax callback onreadystatechange

I first noticed this bug a few days after upgrading to FireFox 3.5. When you fire an XHR request, the callback function is not being executed when the request completes itself. Instead you see an onreadystatechange error in Firebug.

There have been several bugs reports on this:

http://www.nczonline.net/blog/2009/07/09/firefox-35firebug-xmlhttprequest-and-readystatechange-bug/
http://www.ghastlyfop.com/blog/2007/01/onreadystate-changes-in-firefox.html

My advice is don’t upgrade too FireFox 3.5 until they have released a patch for this bug. Its incredibly annoying to keep retrying your XHR request until it finally succeeds knowing your code is just fine. I have downgraded both my systems to FireFox 3.0.11. My bigger concern is how this ever got passed of by QA?

Chris Nizzardini

Chris Nizzardini has been developing web applications since 2006. He lives and works in beautiful Salt Lake City, Utah. If you’re interested in hiring me for contract work please visit IO Spring LLC.