select + option + optgroup element

with label

with label + selected on option a

with label + required

with label + disabled

with size attribute

with size + multiple attribute

with label and optgroup

Code

<label> choose
<select>
<optgroup label="part 1">
<option value="1">a</option>
<option value="2">b</option>
</optgroup>
<optgroup label="part 2">
<option value="1">a</option>
<option value="2">b</option>
</optgroup>
</select>
</label>

Reference