function getXMLHttpRequest(){
	if(window.ActiveXObject){
		try{ return new ActiveXObject("Msxml2.XMLHTTP"); }
		catch(e){
			try{ return new ActiveXObject("Microsoft.XMLHTTP"); }
			catch(e1){ return null; }
		}
	}
	else if(window.XMLHttpRequest) return new XMLHttpRequest();
	else return null;
}

var httpRequest = null;

function sendRequest(url, params, callback, method){
	httpRequest = getXMLHttpRequest();
	var httpMethod = method ? method : 'GET';
	if(httpMethod != 'GET' && httpMethod != 'POST'){
		httpMethod = 'GET';
	}

	var httpParams = (params == null || params == '') ? null : params;
	var httpUrl = url;

	if(httpMethod == 'GET' && httpParams != null){
		httpUrl = httpUrl + "?" + httpParams;
	}

	httpRequest.open(httpMethod, httpUrl, true);
	httpRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
	httpRequest.onreadystatechange = callback;
	httpRequest.send(httpMethod == 'POST' ? httpParams : null);
}