function for making Ajax requests.
function makeRequest(url, callback) { var request; if (window.XMLHttpRequest) { request = new XMLHttpRequest(); // IE7+, Firefox, Chrome, Opera, Safari } else { request = new ActiveXObject("Microsoft.XMLHTTP"); // IE6, IE5 } request.onreadystatechange = function() { if (request.readyState == 4 && request.status == 200) { callback(request); } } request.open("GET", url, true); request.send(); }