vue写省市级联动

<template>
    <div>
      <!-- 省 -->
      <select v-model="provinceid" @change="updatCity()">
          <option v-for="(item,index) in provinceArr" :value="item.name" :key="index" >{{item.name}}</option>
      </select>
      {{provinceid}}
        <!-- 市 -->
      <select v-model="shi" @change="updatShi()">
          <option v-for="(item,index) in shiArr" :key="index" :value="item.name" >{{item.name}}</option>
      </select>
        {{shi}}
        <select  v-model="qu"  >
          <option v-for="(item,index) in quArr" :key="index" :value="item">{{item}}</option>
      </select>
      {{qu}}
    </div>
</template>

<script>
export default{
    data(){
        return{
            // 数据
            // 存放默认市的
            provinceid:'北京市',
             provinceArr:[{
                name: "北京市",
                city: [{
                    name: "北京市",
                    districtAndCounty: ["东城区", "西城区", "崇文区", "宣武区", "朝阳区", "丰台区", "石景山区", "海淀区", "门头沟区", "房山区", "通州区", "顺义区", "昌平区", "大兴区", "怀柔区", "平谷区", "密云县", "延庆县", "延庆镇"]
                }]
            }, {
                name: "重庆市",
                city: [{
                    name: "重庆市",
                    districtAndCounty: ["渝中区", "大渡口区", "江北区", "沙坪坝区", "九龙坡区", "南岸区", "北碚区", "万盛区", "双桥区", "渝北区", "巴南区", "万州区", "涪陵区", "黔江区", "长寿区", "合川市", "永川区市", "江津市", "南川市", "綦江县", "潼南县", "铜梁县", "大足县", "荣昌县", "璧山县", "垫江县", "武隆县", "丰都县", "城口县", "梁平县", "开县", "巫溪县", "巫山县", "奉节县", "云阳县", "忠县", "石柱土家族自治县", "彭水苗族土家族自治县", "酉阳土家族苗族自治县", "秀山土家族苗族自治县"]
                }]
            }, {
                name: "河北省",
                city: [{
                    name: "石家庄市",
                    districtAndCounty: ["长安区", "桥东区", "桥西区", "新华区", "裕华区", "井陉矿区", "辛集市", "藁城市", "晋州市", "新乐市", "鹿泉市", "井陉县", "微水镇", "正定县", "正定镇", "栾城县", "栾城镇", "行唐县", "龙州镇", "灵寿县", "灵寿镇", "高邑县", "高邑镇", "深泽县", "深泽镇", "赞皇县", "赞皇镇", "无极县", "无极镇", "平山县", "平山镇", "元氏县", "槐阳镇", "赵县", "赵州镇"]
                }, {
                    name: "张家口市",
                    districtAndCounty: ["桥西区", "桥东区", "宣化区", "下花园区", "宣化县", "张家口市宣化区", "张北县", "张北镇", "康保县", "康保镇", "沽源县", "平定堡镇", "尚义县", "南壕堑镇", "蔚县", "蔚州镇", "阳原县", "西城镇", "怀安县", "柴沟堡镇", "万全县", "孔家庄镇", "怀来县", "沙城镇", "涿鹿县", "涿鹿镇", "赤城县", "赤城镇", "崇礼县", "西湾子镇"]
                }, {
                    name: "承德市",
                    districtAndCounty: ["双桥区", "双滦区", "鹰手营子矿区", "承德县", "下板城镇", "兴隆县", "兴隆镇", "平泉县", "平泉镇", "滦平县", "滦平镇", "隆化县", "隆化镇", "丰宁满族自治县", "大阁镇", "宽城满族自治县", "宽城镇", "围场满族蒙古族自治县", "围场镇"]
                }, {
                    name: "秦皇岛市",
                    districtAndCounty: ["海港区", "山海关区", "北戴河区", "昌黎县", "昌黎镇", "抚宁县", "抚宁镇", "卢龙县", "卢龙镇", "青龙满族自治县", "青龙镇"]
                }]

            }],
            // 存放默认市的
            shi:"北京市",
            shiArr:[{name:"北京市"}],
            // 存放默认区的
            qu:"东城区",
            quArr:["东城区"]
        }
    },
    methods:{
        // 方法  切换城市要改变数据 
       updatCity(){
           var ref=this;
         this.provinceArr.forEach(function(item,index){
             if(item.name==ref.provinceid){
                 ref.shiArr=item.city;
                ref.shi=ref.shiArr[0].name; 
                 return;
             }
         })
            this.shiArr.forEach(function(item,index){
             if(item.name==ref.shi){
                 ref.quArr=item.districtAndCounty;
                  ref.qu=ref.quArr[0];
                 return;
             }
         }) 
         
       },
       updatShi(){
              var ref=this;
             this.shiArr.forEach(function(item,index){
             if(item.name==ref.shi){
                 ref.quArr=item.districtAndCounty;
                  ref.qu=ref.quArr[0];
                 return;
             }
         }) 
       }

    }

}
</script>

<style></style>