//create a XMLHttpRequest Object.
if(window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
}

//call this function with url of document to open as attribute
function requestContent(url) {
xmlhttp.open("GET",url,true);
xmlhttp.onreadystatechange =statusListener;
xmlhttp.send(null);
}

//statusListener function is called automatically whenever readystate value of XMLHttpRequest Object changes.
//see xmlhttp.onreadystatechange =statusListener; statement above.
//When readystate is 1, its a loading state.
//When readystate is 4, content is loaded
function statusListener() {
if (xmlhttp.readyState == 1) {
document.getElementById('content').innerHTML="<div style='text-align:center;'><img src='http://parse.webcastr.com/images/ajax-loader.gif' /></div>";
}

if (xmlhttp.readyState == 4) {
//xmlhttp.responseText is the content of document requested
document.getElementById('content').innerHTML=xmlhttp.responseText;
}
}