Prova cosi:
codice:
<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<title>Form loading</title>

<script type="text/javascript">

function hideProgress(){
        setTimeout(function(){document.getElementById('loader').style.display = 'none';}, 5000);     
}
</script>

</head>

<body>

<div align="center">
<h1 id="loader" style="position: absolute;top: 100px">
[img]/images/please-wait.gif[/img]</h1>


<iframe height="826" onload="hideProgress()" scrolling="no" 
        style="width:100%;border:none" 
        src="WeddingInvitation.asp" 
        title="WeddingInvitation.asp">
Wedding Invitation
</iframe>
</div>

</body>

</html>