function makePOSTRequest(url, parameters) 
{
    http_request = false;
    if (window.XMLHttpRequest) 
	{ 
		// Mozilla, Safari,...
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType) 
		{
        	// set type accordingly to anticipated content type
            //http_request.overrideMimeType('text/xml');
            http_request.overrideMimeType('text/html');
        }
    } else if (window.ActiveXObject) 
	{ // IE
         try {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
         } catch (e) {
            try {
               http_request = new ActiveXObject("Microsoft.XMLHTTP");
            } catch (e) {}
         }
    }
    if (!http_request) 
	{
        alert('Cannot create XMLHTTP instance');
        return false;
    }
      
      http_request.onreadystatechange = alertContents;
      http_request.open('POST', url, true);
      http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      http_request.setRequestHeader("Content-length", parameters.length);
      http_request.setRequestHeader("Connection", "close");
      http_request.send(parameters);
}