Call Web Service via Javascript

 Hello,
I am trying to call a web service in my ASPX page as such: 

url = 'http://localhost/myservice.asmx/GetSummary?accountNumber=123&summaryType=<%# XPath("SummaryType") %>&title=&';
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = processReqChange;
//xmlhttp.onreadystatechange = callbackSummary_<%# XPath("SummaryType").ToString().Replace(" ","") %>;

xmlhttp.open("GET",url,true);
xmlhttp.send(null);This Web Service returns data as string, I want to render this string in a div. Can anyone suggest how to do this?
Thanks.

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