<style>
.span{border:1px solid #000000;overflow:hidden;width:68;}
.select{width:72;margin:-2;}
</style>
<span class="span">
<select class="select" >
<option selected>字体大小</option>
<option value="12px">12px</option>
<option value="14px">14px</option>
<option value="16px">16px</option>
<option value="18px">18px</option>
<option value="20px">20px</option>
<option value="22px">22px</option>
<option value="12px">默认大小</option>
</select></span>