codice:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>
<head>
<title>Untitled</title>
</head>
<body>
<script language="JavaScript" type="text/javascript">
<!--
var autoSub;

function autoSubmit() {
  //----- eseguire la funzione _autoSubmit dopo 5 secondi
  autoSub = setTimeout("_autoSubmit()",5000);
} // function autoSubmit()

function _autoSubmit() {
 //------ cancellazione del riferimento 
 clearTimeout(autoSub);  
 //------ submit della pagina
 document.forms.myform.submit();  
} // _autoSubmit()

autoSubmit();
//-->
</script>



<form id="myform" method="post" action="test152b.html">
<input type="text" name="t1">
</form>
</body>
</html>