<select id="abc">
<optgroup label="aaa">
<option>1233 </option>
<option>1233 </option>
<option>1233 </option>
</optgroup>
</select>
<optgroup label="aaa">
<option>1233 </option>
<option>1233 </option>
<option>1233 </option>
</optgroup>
</select>