Passing params to PHP served paged in iFrame...

Dear all, Not so simple question. Here's what I'm trying to do. I want to be able to provide a simple script tag pair so that my client's can cut and paste it into their site. This is to try and to make it as simple as posisble for them ;-) The script is then meant to write an iFrame into the document, using the served PHP file for the source. So far, so good. Now for the tricky part. I want the PHP file to include a pop-up menu which calls a script in the calendar.js file, which in turn reloads (using replace so that the back button doesn't break) the served page, but with an updated parameter - essentially the new year and month to display. Here are the bare bones of my not-quite-functioning solution. (I'm using Firefox - once I get it working I realise I'll need to tweak how I get the object to do the replace on, and indeed the replace function itself for IE 5 etc...) The alert is working (so the parameter is being passed), but the reload isn't. What am I doing wrong? Hope some passing geniuses out there can help/have cracked this one before. R **** example client.html file as follows: -------- <html> <head>

    <title>Client</title>

</head> <body>

    <h3>Calendar</h3>
    <script type="text/javascript" src="calendar.js"></script>

</body> </html> ------- **** calendar.js file as follows: -------- document.write('<iframe id="calendarFrame" src="server.php">'); document.write('</iframe>'); function reloadCalendar(yearMonth) { alert(yearMonth); var URL = 'server.php?yearmonth=' + yearMonth; document.getElementById('calendarFrame').location.replace(URL); return false; } --------- ****server.php file as follows: --------- <html> <head>

    <title>Server</title>

</head> <body> <form name="emailForm" id="emailForm" action="server.php"> <select name="yearmonth" onchange="top.reloadCalendar(this.value);">

    <option value="2006-05">May 2006</option>
    <option value="2006-06">Jun 2006</option>
    <option value="2006-07">Jul 2006</option>

</select <?php $ym = $_REQUEST['yearmonth']; echo "show calendar for $ym"; ?> </body> </html> ---------