function obtenerXHR()
{
	var req;
	if (typeof XMLHttpRequest == "undefined" )
	{
		if(navigator.userAgent.indexOf("MSIE 5") >= 0)
		{
			req = new ActiveXObject("Microsoft.XMLHTTP");
		}
		else
		{
			req = new ActiveXObject("Msxml2.XMLHTTP");
		}
	}
	else
	{
		req=new XMLHttpRequest();
	}
	return req;
}


/*function obtenerXHR() 
{
	req = false;
	if (window.XMLHttpRequest) 
	{
		req = new XMLHttpRequiest();
	} 
	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;
}*/