Maybe it is not right place to ask this question, but still decided to ask.
How does XMLRPC connection happen in JS XMLRPC?
how can I establish XMLRPC connection between C code server and JS client?
wow, there's a blast from the past; i though xmlrpc went the way of the dinos...
anyways, the answer to your question is ajax and lots of string building of xml. you send a POST of the built-up xml string with ajax, and then the server's response xml gets parsed for the data you want.