How can I find out which Javascript causes an Ajax request?

Question

I'm having a problem with a Java JSF application: In a certain case, a user action causes an Ajax HTTP request that updates the UI correctly, but then immediately a second request is triggered, causing a second, incorrect update.

How can I find out (preferably using Firebug) where exactly that second request is triggered? There's a lot of minified framework JS code, so I don't know where to place breakpoints. Setting the form onsubmit handler to console.trace did not help, I suppose because these are independant Ajax requests.

Answer 1

While trying out the suggestions in the answers, I found that Firebug already has exactly what I need out of the box: the Console tab displays all requests, and for Ajax requests it shows the file and line number where they originate, which tells me where to set my breakpoint...