添加以下代码  选择到最后一级时再点"不限"按钮返回到省一级的该怎么修改下呢

<dl><dt>区域:</dt><dd>

                <!--先显示省份 如果选了省份就隐藏掉 不隐藏就删除if 语句--> 

       {if !input('province_id')} 

       <a href='{:urls("index",fun("field@make_filter_url","zone_id,city_id,page"))}' {if input('province_id')===null} class="ck"{/if}>不限</a> 

       {volist name=":get_area('','',0)" id="name"} 

       <a href='{:urls("index","province_id=$key&".fun("field@make_filter_url","province_id,page"))}' {if input('province_id')==$key} class="ck"{/if}>{$name}</a>

       {/volist}

     {/if} <br>

     <!--选择了省份显示全部市区 选择市区后隐藏掉市区 --> 

     {if input('province_id')&&!input('city_id')} 

       <a href='{:urls("index",fun("field@make_filter_url","zone_id,city_id,page"))}' {if input('city_id')===null} class="ck"{/if}>不限</a> 

       {volist name=":get_area('','',input('province_id'))" id="name"} <a href='{:urls("index","city_id=$key&".fun("field@make_filter_url","city_id,page"))}' {if input('city_id')==$key} class="ck"{/if}>{$name}</a> {/volist}

     {/if} 

     <!--选择了市区就显示县 选择了县隐藏县--> 

     {if input('city_id')&&!input('zone_id')} 

       <a href='{:urls("index",fun("field@make_filter_url","zone_id,page"))}' {if input('zone_id')===null} class="ck"{/if}>不限</a> 

       {volist name=":get_area('','',input('city_id'))" id="name"} 

       <a href='{:urls("index","zone_id=$key&".fun("field@make_filter_url","zone_id,page"))}' {if input('zone_id')==$key}class="ck"{/if}>{$name}</a>

       {/volist}

     {/if} 

     <!--最后一级的街道--> 

     {if input('zone_id')}

       <a href='{:urls("index",fun("field@make_filter_url","street_id,page"))}' {if input('street_id')===null} class="ck"{/if}>不限</a>

       {volist name=":get_area('','',input('zone_id'))" id="name"} 

       <a href='{:urls("index","street_id=$key&".fun("field@make_filter_url","street_id,page"))}' {if input('street_id')==$key}class="ck"{/if}>{$name}</a> 

       {/volist}

     {/if}

    </dd></dl>