How to load jquery in gadget.

function DoInit() {
           $("#gadgetContent").append("<br />Loaded Jquery b4 execute");
           var xhr = new XMLHttpRequest();
           var requestUrl = "http://yourip:port/Webservice.asmx/yourmethod";
           xhr.open("GET", requestUrl, false);
           xhr.send(null);
           if (xhr.status == 200) {
               var image_url = xhr.responseText;
               $("#gadgetContent").append("<br /> Data is <br />" + image_url);
           }
           $("#gadgetContent").append("<br />Loaded after execution");
       }