JQuery Validation

[eluser]Mark van der Walle[/eluser]
First to answer your last question: JSON is alot faster for javascript so if your url is only used for javascript json is the way to go.

Then the first question. You almost got it right except that this:

Code:

success: function(responseXML) {
   // responseXML is XML document object
   var data = $('myElement', responseXML).text();
}

will take part of the XML and put it into the data variable. Where the XML is something like:
<myElement>The contents that are being put into the data variable</myElement>