效果图如下：
<h2>Cars Select</h2>
<div class="select">
<select name="cars">
<option value="volvo">Volvo</option>
<option value="saab">Saab</option>
<option value="opel" selected>Opel</option>
<option value="audi">Audi</option>
</select>
</div> <h2>Cars Select</h2>
<div class="
