Load Page in a Div using Ajax with JQuery in PHP

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Test</title>
<script type="text/javascript">
    window.onclick = function () {
        document.getElementById("aside").innerHTML = "<img src='loadingImage.gif'>";
        if (XMLHttpRequest) var x = new XMLHttpRequest();
        else var x = new ActiveXObject("Microsoft.XMLHTTP");
        x.open("GET", "other_page.php?aa=1&bb=4&cc=6", true);
        x.send("");
        x.onreadystatechange = function () {
            if (x.readyState == 4) {
                if (x.status == 200) document.getElementById("aside").innerHTML = x.responseText;
                else document.getElementById("aside").innerHTML = "Error loading document";
            }
        }
    }
</script>
</head>
<body>
<div id="aside1" onclick="asd()">This is aside</div>
<div id="aside"></div>
</body>
</html>