x
1
<select>2
3
<optgroup label="Swedish Cars">4
5
<option value="volvo">Volvo</option>6
7
<option value="saab">Saab</option>8
9
</optgroup>10
11
<optgroup label="German Cars">12
13
<option value="mercedes">Mercedes</option>14
15
<option value="audi">Audi</option>16
17
</optgroup>18
</select>