function obtenerXHR(){
	req = false;
	if(XMLHttpRequest){
		req = new XMLHttpRequest();
	}
	else{
		if(ActiveXObject){
			var vectorVersiones = ["MSXML2.XMLHttp.5.0","MSXML2.XMLHttp.4.0","MSXML2.XMLHttp.3.0","MSXML2.XMLHttp","Microsoft.XMLHttp"];
			for(var i=0; i<vectorVersiones.length; i++){
				try{
					req = new ActiveXObject(vectorVersiones[i]);
					return req;
				}
				catch(e){}
			}
		}
	}
	return req;
}