select onchange事件，选择第一个时没反应

<select id="zhouqi" class="select" size="1" name="periodicId" style="color:gray;" >
                                            <option value="0" selected="selected" style="display: none;"></option>
                                            <option value="0" >选择团期</option>
                                            <foreach name='skuCategoryInfo.periodicList' item='periodic' key="key">
                                                <option value="{$key}">团期编号{$key}</option>
                                            </foreach>
 </select>
<select id="zhouqi" class="select"