Scusa, non ho letto con attenzione tutto il post

codice:
<script>
function submitIt(theform) { 
if ((theform.email.value =="")|| 
(theform.email.value.indexOf("@") == -1) || 
(theform.email.value.indexOf(".") == -1) || 
(theform.email.value.length < 7)) 
{ 
alert("Manca l'email..."); 
theform.email.focus(); 
return false; 
} 
window.open('','mailingList','toolbar=0,location=0,status=0,menubar=0,scrollbars=0,resizable=1,width=400,height=200')
} 
--> 
</script> 
</head> 
<body OnLoad="document.frmMailingList.nome.focus();"> 
<form name="frmMailingList" method="post" 
 action="mailing_list.asp" target="mailingList"
 onSubmit="return submitIt(this)">
ciao