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);
}