Una soluzione "semplice"

codice:
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style>INPUT {border:0 none white;}</style>
</head>
<body>
<form name=panel><input type=text name=mess></form>
</body>
</html>

e poi...

codice:
<script language='javascript'>
<!--//
myFloater = window.open('pagina.htm','myWindow','scrollbars=no,status=no,width=200,height=100')

function increment(runOnce) {
m = myFloater.document.panel.mess;
if (runOnce == 1) {
m.value="ATTENDERE PREGO....";
}
else {
v = parseFloat("0"+m.value) +1;
m.value = ""+v+"%";
}
}
//-->
</script>
... ma devi sperimentare per stabilire gli intervalli ed i valori visualizzati...

ciao