Q413 How can I return the text values from a multiple select box back to a form on the opener window?

<script language="JavaScript"><!--
function myopen() {
    popupWindow=open('multiple.htm','windowName','resizable=no,width=400,height=300');
    if (popupWindow.opener == null) popupWindow.opener = self;
}
//--></script>

<form>
<input type="text" size="40" name="resultfield">
<input type="button" value="Open" onClick="myopen()">
</form>

<script language="JavaScript"><!--
function update() {
    var output = '';

    for (var i=0;i < document.forms[0].selectfield.options.length;i++) {
         if (document.forms[0].selectfield.options[i].selected) {
             output += document.forms[0].selectfield.options[i].text + ' ';
         }
     }

    opener.document.forms[0].resultfield.value = output;
    window.close();
}
//--></script>

<form onSubmit="return false">
<select multiple name="selectfield">
<option>Monday
<option>Tuesday
<option>Wednesday
<option>Thursday
<option>Friday
<option>Saturday
<option>Sunday
</select>
<p>
<input type="button" value="Update" onClick="update()">
</form>