var returned_data;
var request = new XMLHttpRequest();

function initializeWebservice()
{
var url="http://webserviceprovider.org/Leadservice.asmx
GetLeadCounts?UserName=Prajeesh&Password=123456";; //Web service url
request.onreadystatechange = webStatusProc;
request.open( "GET", url, true );
request.send();
}

function webStatusProc()
{
if (request.readyState == 4) // checking request completed or not?
{
response = request.responseXML.toXML();
XML = XMLDOM.parse( response);
returned_data= XML.evaluate('string(/int)');
alert(returned-data); //alerted returned data for testing
//you can do anything with returned data
}
}