Dynamic select options
HTML
<select multiple="multiple">
<option value="val1">opt1</option>
<option value="val2">opt2</option>
<option value="val3">opt3</option>
</select>
<p></p>
JavaScript
function displayVals() {
var vals = $('select').val() || [];
$('p').html('' + vals.join(", "));
}
$('select').change(displayVals);
displayVals();