<select onchange="selectClassType();"  
        data-errormessage-value-missing=" " 
        class="form-control validate[required, custom[attendeesNumber]]"  
        name="attendees_number" id="attendees_number">
    <option value="0">Choose Attendees Number</option>
    <?php foreach ($virtual_classroom_attendees_number as $v_virtual_classroom_attendees_number) { ?>
        <option value="<?php echo $v_virtual_classroom_attendees_number->virtual_classroom_attendees_number ?>"><?php echo $v_virtual_classroom_attendees_number->virtual_classroom_attendees_number ?></option>
    <?php } ?>
</select>