SOLVED...
Got it working... finally...
Here is my working multisite index.php:
<head>
</head>
<script type="text/javascript">
function setOptions(chosen){
var selbox = document.formName.ip;
selbox.options.length = 0;
if (chosen == " ") {
selbox.options[selbox.options.length] = new Option('No site selected',' ');
}
if (chosen == "1") {
selbox.options[selbox.options.length] = new Option(' ',' ');
selbox.options[selbox.options.length] = new Option('HOSTNAME1','IP1');
selbox.options[selbox.options.length] = new Option('HOSTNAME2','IP2');
}
if (chosen == "2") {
selbox.options[selbox.options.length] = new Option(' ',' ');
selbox.options[selbox.options.length] = new Option('HOSTNAME3','IP3');
selbox.options[selbox.options.length] = new Option('HOSTNAME4','IP4');
}
}
</script>
<form name="formName" method="post" action="polycom-reboot.php">
Conference Phone Reboot
<select name="site" size="1" onchange="setOptions(document.formName.site.options[document.formName.site.selectedIndex].value);">
<option value=" " selected="selected"></option>
<option value="1">Site1</option>
<option value="2">Site2</option>
</select>
<select name="ip" size="1" method="post" action="polycom-reboot.php">
<option value=" " selected="selected">No phone selected</option>
</select>
<input type="submit" value="Reboot..."/>
</form>
</body>
</html>