ASP.Net Ajax compatibility

I need to write an application running on the internet. So I suggested to write it using ASP.net Ajax. But I need to know how is the compatibility of ASP.Net Ajax with other browsers and different versions?Which resources works on a specific browser and which doesn't work.Basically, I need my application working on IE 5+. Will Ajax run on this scenario?Ajax is built on pieces that are available in most recent browsers. I'm pretty sure IE 5.0 is included in the list. If you use Atlas, which is the ASP.Net implementation of programming with Ajax, you'll get browser compatability and their list of supported browsers should be availablehere.