function pedir_numero_visitas()
{
	url = "pedir_numero_visitas.php";
	if (window.XMLHttpRequest)
	{
	    req = new XMLHttpRequest();
	    req.onreadystatechange = processReqVisitas;
	    req.open("GET", url, true);
	    req.send(null);
	}
	else if (window.ActiveXObject)
    {   isIE = true;
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req)
        {   req.onreadystatechange = processReqVisitas;
            req.open("GET", url, true);
            req.send();
        }
    }
}

function processReqVisitas()
{
    if (req.readyState == 4)
    {
        if (req.status == 200)
        {
			response  = req.responseText;
			document.getElementById('numero_visitas').innerHTML=response;
        }
        else
        {
            pedir_numero_visitas();
        }
    }
}