var http_request = false;
function getXmlHttpRequestObject() {
      http_request = false;
      if (window.XMLHttpRequest) { // Mozilla, Safari,...
         http_request = new XMLHttpRequest();
         if (http_request.overrideMimeType) {
         	// set type accordingly to anticipated content type -- to avoid error in Firefox
            //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;
      }
      
      return http_request;
	
}
function ajaxPostRequest(request, url, handlingFunction, parameters) {

    request.onreadystatechange = handlingFunction;
        request.open('POST', url, true);
		request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
		request.setRequestHeader("Content-length", parameters.length);
		request.setRequestHeader("Connection", "close");
		request.send(parameters);
}