Tools for Ajax load testing

Question

There seems to be a lot of stress/load testing tool that support AJAX.
I am wondering how well does these tool implemented.

Do they only record http request and repl

Answer 1

I've successfully used JMeter to load test our Ajax (JSF/RichFaces) application. I didn't bother with JMeter's recording tool - rather I used the HttpFox plugin for Firefox to monitor what the browser is POST-ing to the server and I recreated this in JMeter.

It did get a bit complex, but the load test is now fairly robust. JMeter has all kinds of useful 'elements' to extract ID's from a web page, perform conditional logic, increment counters etc.