Differ XML and HTML from AJAX request

Differ XML and HTML from AJAX request

Hello! I'm totally new to the AJAX function of jQuery. I'm about to develop a dynamic page. But the problem is, that I'm sending a request and the answer could be a HTML or a XML document. There is absolutley now way, that I can dicide what type the server is sending me! So I was looking for a way, to decide whether the answer is a XML or a HTML document. What I'd like to have too, is the possibility, when I have a HTML document as answer, that I can access the nodes and stuff like my current DOM. Is that possible?

If you have questions, just ask me. I don't know, if this question was asked before, but I don't think so. If this question was asked before and you know the thread, please give me the link!

Thank you!