<script type="text/javascript">
function go() {


while (1 == 2) // loop infinito
{
setInterval(function(){Popup(1)},20000);
setInterval(function(){Popup(2)},20000);
setInterval(function(){Popup(3)},20000);
setInterval(function(){Popup(4)},20000);

setTimeout("go()",3000);
}

}

</script>
</head>
<body onload="go();">