var req = new XMLHttpRequest();
...
req.send(...);
...
var xmlSerializer = new XMLSerializer();
var markup = xmlSerializer.serializeToString(req.responseXML);
alert("markup="+markup)
I found it
here.
Here is some reference on XMLHttpRequest.
Here is how the object can be used.
# posted by rot13(Unafba Pune) @ 1:38 PM