var http_request = false;
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);
}