Refreshing DIV content with AJAX

<!--
// Customise those settings
 
var seconds = 5;
var divid = "timediv"; // div that need to refresh
var url = "boo.php"; // php file that contains code
 
////////////////////////////////
//
// Refreshing the DIV
//
////////////////////////////////
 
function refreshdiv(){
 
// The XMLHttpRequest object
 
var xmlHttp;
try{
xmlHttp=new XMLHttpRequest(); // Firefox, Opera 8.0+, Safari
}
catch (e){
try{
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP"); // Internet Explorer
}
catch (e){
try{
xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e){
alert("Your browser does not support AJAX.");
return false;
}
}
}
 
// Timestamp for preventing IE caching the GET request
 
fetch_unix_timestamp = function()
{
return parseInt(new Date().getTime().toString().substring(0, 10))
}
 
var timestamp = fetch_unix_timestamp();
var nocacheurl = url+"?t="+timestamp;
 
// The code...
 
xmlHttp.onreadystatechange=function(){
if(xmlHttp.readyState==4){
document.getElementById(divid).innerHTML=xmlHttp.responseText;
setTimeout('refreshdiv()',seconds*1000);
}
}
xmlHttp.open("GET",nocacheurl,true);
xmlHttp.send(null);
}
 
// Start the refreshing process
 
var seconds;
window.onload = function startrefresh(){
setTimeout('refreshdiv()',seconds*1000);
}
-->

<!--
<script src="ajax.js">
 
<strong>This is the current date and time (updates every 5 seconds):</strong>
 
<script type="text/javascript"><!--
refreshdiv();
// --></script>
<div id="timediv"></div>   // this is going to be refreshed
-->

<!--
<?
// Format time output
 
$str = "It is %a on %b %d, %Y, %X - Time zone: %Z";
 
// Echo results
 
echo(gmstrftime($str,time()));
 
?>
-->