function objetoAjax()
	{
		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;
	}

	ajax=objetoAjax();
	ajax.open("GET", "contador.php?ref="+document.referrer );
	ajax.send(null)