Mega Code Archive
Select multiple options in a dropdown list (option)
<![CDATA[
<html>
<head>
<script type="text/javascript">
function formAction(){
var x=document.getElementById("aSelectControl")
x.multiple=true
}
</script>
</head>
<body>
<form>
<select id="aSelectControl" size="3">
<option>Java</option>
<option>PHP</option>
<option>Perl</option>
</select>
<input type="button" onclick="formAction()" value="Set to Select multiple">
</form>
</body>
</html>
]]>