//html結(jié)構(gòu)
 <el-select v-model="hospital" @visible-change="visible" placeholder="請(qǐng)選擇醫(yī)院" filterable collapse-tags multiple @change='changeHospital'>
     <el-option :disabled="loading" :label="item.hospital_name" :value="item.hospital_id" v-for="(item,index) in hospitalList" :key="item.hospital_id"></el-option>
 </el-select>

//js代碼

 // 下拉框出現(xiàn)的時(shí)候事件
  visible(val){
 		 //如果多個(gè)下拉框，需要具體給某個(gè)標(biāo)簽綁定
        let scroll = document.querySelectorAll('.el-scrollbar__wrap')
        //顯示的時(shí)候綁定，隱藏的時(shí)候移出綁定事件
        if(val){
             scroll[1].addEventListener('scroll',this.scrollLoad)
        }else{
             scroll[1].removeEventListener('scroll',this.scrollLoad)
         }
   },
    // 下拉框滾動(dòng)分頁(yè)加載數(shù)據(jù)
    scrollLoad(e){
         const { target: { clientHeight,scrollHeight,scrollTop } } = e
         const step = 100 //間隔，距離底部100的時(shí)候加載數(shù)據(jù)
         const len = this.hospitalList.length //獲取當(dāng)前展示的醫(yī)院列表長(zhǎng)度
         if(len >= this.hospital_list.length)return //數(shù)據(jù)加載完畢
         //從總列表里每次 截取一段數(shù)據(jù)，以便后期追加到頁(yè)面
         // 每次追加20條
         const data = this.hospital_list.slice(len,len + 20)
         //判斷觸底加載數(shù)據(jù)    
         if(clientHeight + scrollTop >= scrollHeight - step){
              this.hospitalList.push(...data)
              console.log('觸底加載數(shù)據(jù)');
         }
   }