javascript - Use jQuery to replace XMLHttpRequest -

i quite new javascript libraries. wanted replace current code jquery. current code looks this:

var req;  function createrequest() {    var key = document.getelementbyid("key");    var keypressed = document.getelementbyid("keypressed");    keypressed.value = key.value;    var url = "/my_servlet/response?key=" + escape(key.value);    if (window.xmlhttprequest) {       req = new xmlhttprequest();    } else if (window.activexobject) {       req = new activexobject("microsoft.xmlhttp");    }    req.open("get", url, true);    req.onreadystatechange = callback;    req.send(null); }  function callback() {    if (req.readystate == 4) {       if (req.status == 200) {          var decimal = document.getelementbyid('decimal');          decimal.value = req.responsetext;       }    }    clear(); } 

i wanted replace code little friendlier jquery's

$.get(url, callback); 

however doesn't call callback function.

also call function called createrequest continuously. jquery have nice way of doing that? ­­­­­­­­­­­­­­­­­­­­­­­

$.get(url, {}, callback); 

should trick. callback simplified this:

function callback(content){     $('#decimal').val(content); } 

or shorter:

$.get(url, {}, function(content){     $('#decimal').val(content); }); 

and in think should work:

function createrequest() {     var keyvalue = $('#key').val();     $('#keypressed').val(keyvalue);     var url = "/my_servlet/response";     $.get(url, {key: keyvalue}, function(content){         $('#decimal').val(content);     }); }