multi select
$('#my-select').multiSelect() from http://loudev.com/
by Andy Bulka
HTML
<script src="https://dl.dropboxusercontent.com/u/2019810/scripts/jquery.multi-select.js"></script>
<link rel="stylesheet" href="https://dl.dropboxusercontent.com/u/2019810/scripts/multi-select.css">
<select multiple="multiple" id="my-select" name="my-select[]">
<option value='http://elem_1'>elem 1</option>
<option value='elem_2'>elem 2</option>
<option value='elem_3'>elem 3</option>
<option value='elem_4'>elem 4</option>
<option value='elem_100'>elem 100</option>
</select>
JavaScript
$('#my-select').multiSelect()