To send the document you will need the XmlHttpRequest, either the Microsoft ActiveX version or the built-in one in Gecko based browsers, Netscape, FireFox etc.
Once you have an instance you call the open method specifying the method, URL and whether to wait for return or carry on processing, you then send the data:
HttpReq.open("POST", <url to server here>, true); //blocks until server acknowledges or timeout occurs.
There are plenty of examples in the Microsoft XML sdk and a google search of XmlHttpRequest should show you some cross browser techniques to retrieve the intial XmlHttpRequest object.
Joe (Microsoft MVP - XML