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Paul Rosania

Hi! I'm Paul. I work at Balsa.
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Buyer Beware: Firebug 1.6 + Firefox 4 Beta

November 9, 2010

There is a bug in Firefox 4 beta 6 (#557791) that interferes with Firebug’s “XHR Spy” feature (Firebug issue #3223). The net effect is that XmlHttpRequest onReadyStateChange events don’t fire.

With JQuery, this manifests through $.ajax calls: success and error handlers don’t fire.

The workaround is to uncheck the “Show XmlHttpRequests” option in the Console panel.

For more details, see Firebug’s Known Issues page.

Hopefully this short post saves someone more time than I lost dealing with this bug today.