I'm still kind of new to using AJAX, but I've written a nice little utility for my website. I am now looking at writing something more robust and I wanted to get some advice.

I have an XML file that holds product info. I want the user to be able to select a few search filters and have the data on the page reload showing only those. For example, when someone visits the page, all products will be shown. If someone is looking for a blue product, they can select that and only those will be shown.

I have started using JQuery and think for this I may have to switch to JSON (instead of native XMLDOM).

Does anyone have any other advice for how I should handle the search function? Does this occur on a server-side script? What about using XPath, and XQuery. I've read those aren't as powerful, and people have pretty much made the switch to JSON. Is this true?