可以根据所选的选项动态更改选择框的宽度，而不是使用px固定选择下拉列表的宽度。例如，取决于选择框将调整大小的日期。
<select name="day" class="activity-filter" >
<option value="/customer/8708?day=Any+Day">Any Day</option>
<option value="/customer/8708?day=Mon">Monday</option>
<option value="/customer/8708?day=Tue">Tuesday</option>
<option value="/customer/8708?day=Wed">Wednesday</option>
<option value="/customer/8708?day=Thu">Thursday</option>
<option value="/customer/8708?day=Fri">Friday</option>
<option value="/customer/8708?day=Sat">Saturday</option>
<option value="/customer/8708?day=Sun">Sunday</option>
</select>