function init_xmlhttp()
{
	xmlhttp = GetXmlHttpObject();
	xmlhttp_menu = GetXmlHttpObject();
	xmlhttp_content = GetXmlHttpObject();
	if (xmlhttp==null)
	{
	    alert ("Browser does not support HTTP Request");
	    return;
	}
}

function GetXmlHttpObject()
{
  if (window.XMLHttpRequest)
	    return new XMLHttpRequest();
  if (window.ActiveXObject)
	    return new ActiveXObject("Microsoft.XMLHTTP");
    return null;
}