<div id="app"><div style="margin-bottom: 4px;">  <span class="selectedItem" v-for="item in selectedItems">{{item.name}} <i class="red fa fa-close (alias)"  v-on:click="deleteSelectedItem($index)"></i></span>  <input v-model="inputItem" type="text" v-on:focus="showDropmenu" v-on:keyup.enter="addItem"></div><div v-show="isShowDropmenu">  <button v-for="item in cataName" v-on:click="showCataList($index)">{{item.name}}</button>  <button v-on:click="hideDropmenu"><i class="red fa fa-close (alias)"></i></button>  <div v-for="item in cataList" v-show="item.isShow">    <span v-for="one in item.items" class="item" v-on:click="addByClick(one)">{{one}}</span>  </div></div></div>

new Vue({    el:'#app',    data:{      selectedItems: [{        name: 'NodeJs'      }],      isShowDropmenu: false,      inputItem:'',      cataName:[{name:'开发语法'}, {name: '系统设备'}],      cataList:[{        isShow: true,        items:['js','c++','java']      },{        isShow: false,        items:['windows','chrome','linux']      }]    },    methods:{      showDropmenu: function(event){        console.log('showDropmenu');        this.isShowDropmenu = true;      },      hideDropmenu: function(event){        this.isShowDropmenu = false;        console.log('hideDropmenu');      },      test: function(){        console.log('test');      },      addItem: function(){        this.selectedItems.push({name: this.inputItem});        this.inputItem = "";      },      deleteSelectedItem: function(index){        this.selectedItems.splice(index, 1);      },      showCataList: function(index){        var i = this.cataList.length;        while(i--){          i === index ? this.cataList[i].isShow = true: this.cataList[i].isShow = false;        }      },      addByClick: function(name){        var i = this.selectedItems.length;        while(i--){          if(this.selectedItems[i].name === name){            return;          }        }        this.selectedItems.push({name: name});      }    }  });