In the Definitive Guide to symfony
Chapter 10 - Forms :
// Drop-down list with multiple selection (selected values can be an array)
In The Definitive Guide to symfony - Chapter 10 - Forms
<?php echo select_tag('payment', options_for_select(
array('Visa' => 'Visa', 'Eurocard' => 'Eurocard', 'Mastercard' => 'Mastercard'),
array('Visa', 'Mastercard')
), 'multiple=multiple') ?>
=> <select name="payment" id="payment" multiple="multiple">
<option value="Visa" selected="selected">
<option value="Eurocard">Eurocard</option>
<option value="Mastercard" selected="selected">Mastercard</option>
</select>
The end of the Visa option is missing, it must be replaced by
<option value="Visa" selected="selected">Visa</option>
And the name of the widget is an array (name="payment[]")
<select name="payment[]" id="payment" multiple="multiple">
