<form action="" autocomplete="on">
<input type="submit" value="搜索">
<select name="ss">
<optgroup label="11111">
<option value="A">aaaa</option>
<option value="A">bbbb</option>
<option value="A">cccc</option>
</optgroup>
<optgroup label="22222">
<option value="A" label="就是">1111</option>
<option value="A">2222</option>
<option value="A">3333</option>
</optgroup>
</select>
</form>