[html]
<select>
<option value="A1" attr-data="groupA">A1</option>
<option value="A2" attr-data="groupA">A2</option>
<option value="A3" attr-data="groupA">A3</option>
<option value="B1" attr-data="groupB">B1</option>
<option value="B2" attr-data="groupB">B2</option>
</select>
[/html]
[js]
<script>
var option = $('option:selected', this).attr('attr-data');
</script>
[/js]