  <script type="text/javascript">
function update()
{
    var pageUrl="http://www.mywebsite.com/mypage.html";
    if(typeof ActiveXObject == 'undefined')
    {
        xmlHttpRequest = new XMLHttpRequest();
        xmlHttpRequest.onload = writeIntoMyHTMLBlock;
    }
    else
    {
        xmlHttpRequest = new ActiveXObject("Microsoft.XMLHTTP");
        xmlHttpRequest.onreadystatechange = writeIntoMyHTMLBlock;
    }

    xmlHttpRequest.open("GET", pageUrl, true);
    xmlHttpRequest.send(null);
}

function writeIntoMyHTMLBlock(str)
{
    if(xmlHttpRequest.readyState==4 || xmlHttpRequest.readyState=="complete")  
        document.getElementById('MyHTMLBlock').innerHTML = xmlHttpRequest.responseText;
}

var xmlHttpRequest;
setInterval('update()',10000);
update();
</script>
<div id="MyHTMLBlock"></div> 

