function crearInstancia()
{
	Ajax = false;

	if(window.XMLHttpRequest)
	{
		return new XMLHttpRequest();
	}
	else if(window.ActiveXObject)
	{
		var versiones = ["Msxml2.XMLHTTP.7.0", "Msxml2.XMLHTTP.6.0", "Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"];
		for(var i=0; i<versiones.length; i++)
		{
			try
			{
				Ajax = new ActtiveXObject(versiones[i]);
				if(Ajax)
				{
					return Ajax;
					break;
				}
			}catch(e){};
		}
	}
}

function nuevoAjax(){
 var xmlhttp=false;
 try{
  xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
 }catch(e){
  try {
   xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
  }catch(E){
   xmlhttp = false;
  }
 }

 if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
  xmlhttp = new XMLHttpRequest();
 }

 return xmlhttp;
}