test multiple select

limiter le nb de slection a 2 et forcer l'affichage

HTML

<select name="selector" id="selector" multiple="multiple" data-overlay-theme="c" data-theme="c"  data-icon="grid" data-iconpos="left" data-native-menu="true">
    <optgroup label="Animaux">
        <option value="cheval" selected="selected">cheval</option>
        <option value="mouton">mouton</option>
        <option value="boeuf">boeuf</option>
        <option value="etc">etc</option>
    </optgroup>
    <optgroup label="Objet">
        <option value="Table">Table</option>
        <option value="lampe">lampe</option>
        <option value="etc">etc</option>
    </optgroup>
</select>