checkbox to multiply select
by vi161
HTML
<div class="sel-rad">
<select class="multipleSelect" id="" multiple="multiple" name="00N46000001prf3" title="Contraindication">
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="3">4</option>
</select>
<input type="checkbox" name="num" value="1" class='myClass'/>
<input type="checkbox" name="num" value="2" />
<input type="checkbox" name="num" value="3" />
<input type="checkbox" name="num" value="4" />
</div>
JavaScript
$('.sel-rad').click(function() {
var selected = [];
$("input:checkbox[name=num]:checked").each(function() {
selected.push($(this).val());
});
$('.multipleSelect').val(selected);
});