var http_request = false;

function makePOSTRequest(url, parameters) 
{
	http_request = false;
	if (window.XMLHttpRequest) 
	{ // Mozilla, Safari,...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) 
		{
			http_request.overrideMimeType('text/xml');
		}
	} 
	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);
}