当我触发其中一个的时候，想知道怎么获取他的下标<template><headerclass="header"><pclass="header_mission"><span>任务通知</span><span><ulclass="list"><liclass="li">111</li><liclass="li">222</li><liclass="li">333</li><liclass="li">444</li><liclass="li">555</li></ul></span></p><contentclass="content"><pclass="bg_white"><pclass="content_mission"><span>我的任务<spanstyle="padding:0;">(1)</span></span><span></span><spanid="myMission"class="mui-iconmui-icon-arrowright"@click="myMission"></span></p><pclass="mission_list"><ul><li><spanclass="mission_img"><spanclass="mui-iconmui-icon-plusemptyfile"><pclass="vue-upload-img-multiple"><pv-if="images.length>0"><ul><liv-for="imageinimages"><imgstyle="width:100%;height:100%;position:absolute;top:0;left:0;z-index:9;":src="image"/><ahref="javascript:void(0);"style="position:absolute;top:-30px;right:0;z-index:10;color:red;"><spanclass="mui-iconmui-icon-close"@click='delImage($index)'></span></a></li></ul></p><p><pv-if="!image"><inputtype="file"@change="onFileChange"></p><pv-else><img:src="image"/><button@click="removeImage">Removeimage</button></p></p></p></span></span><spanclass="mission_particulars"><pclass="mission_details"><spanclass="mission_name">【四带】老带新</span><spanclass="mission_score"><span>2</span>分</span></p><pclass="mission_progress"><span>进行中</span></p><pclass="mission_time_evaluation"><spanclass="mission_time">2017年6月</span><spanclass="mission_evaluation">评价:<span>3</span>人</span></p></span></li><li><spanclass="mission_img"><spanclass="mui-iconmui-icon-plusemptyfile"><pclass="vue-upload-img-multiple"><pv-if="img.length>0"><ul><liv-for="imageinimg"><imgstyle="width:100%;height:100%;position:absolute;top:0;left:0;z-index:9;":src="image"/><ahref="javascript:void(0);"style="position:absolute;top:-30px;right:0;z-index:10;color:red;"><spanclass="mui-iconmui-icon-close"@click='delImage($index)'></span></a></li></ul></p><p><pv-if="!image"><inputtype="file"@change="onFileChange"></p><pv-else><img:src="image"/><button@click="removeImage">Removeimage</button></p></p></p></span></span><spanclass="mission_particulars"><pclass="mission_details"><spanclass="mission_name">【四带】老带新</span><spanclass="mission_score"><span>2</span>分</span></p><pclass="mission_progress"><span>进行中</span></p><pclass="mission_time_evaluation"><spanclass="mission_time">2017年6月</span><spanclass="mission_evaluation">评价:<span>3</span>人</span></p></span></li></ul></p></p><pclass="bg_whitemarginTop"><pclass="content_mission"><span>历史任务<spanstyle="padding:0;">(1)</span></span><span></span><spanid="missionHistorical"class="mui-iconmui-icon-arrowright"@click="missionHistorical"></span></p><pclass="mission_historical_list"><ul><li><spanclass="mission_img"><imgsrc="../../imgs/banner/banner_img_01.jpeg"alt=""/></span><spanclass="mission_particulars"><pclass="mission_details"><spanclass="mission_name">【四带】老带新</span><spanclass="mission_score"><span>2</span>分</span></p><pclass="mission_progress"><span>进行中</span></p><pclass="mission_time_evaluation"><spanclass="mission_time">2017年6月</span><spanclass="mission_evaluation">评价:<span>3</span>人</span></p></span></li></ul></p></p><pclass="mission_situation">查看党小组任务情况</p><pid="box"@click='box'><span>这是一个span标签</span></p></content></header></template><scripttype="text/javascript">module.exports={name:'Upload',data:function(){return{images:[],img:[]}},mounted(){this.init();},methods:{box(){varbox1=document.getElementById('box');box1.innerHTML="<p>这是一个P标签</p>";},init(){varlist=document.getElementsByClassName('list')[0];varli=document.getElementsByClassName('li');vari=1;vardatajson;varscoll=function(){if(i==5){i=0;}list.style.top=-43*i+'px';i++;}setInterval(scoll,2000);},myMission(){varmymission=document.getElementById('myMission');varmissionList=document.getElementsByClassName('mission_list')[0];varbgWhite=document.getElementsByClassName('bg_white')[0];varclaName=mymission.className;if(mymission.className=='mui-iconmui-icon-arrowright'){mymission.className="mui-iconmui-icon-arrowdown";missionList.style.display='block';bgWhite.style.paddingBottom="10px";}else{mymission.className='mui-iconmui-icon-arrowright';missionList.style.display='none';bgWhite.style.paddingBottom="0";}},missionHistorical(){varmissionhistorical=document.getElementById('missionHistorical');varmissionHistoricalList=document.getElementsByClassName('mission_historical_list')[0];varbgWhite2=document.getElementsByClassName('bg_white')[1];if(missionhistorical.className=='mui-iconmui-icon-arrowright'){missionhistorical.className="mui-iconmui-icon-arrowdown";missionHistoricalList.style.display='block';bgWhite2.style.paddingBottom="10px";}else{missionhistorical.className='mui-iconmui-icon-arrowright';missionHistoricalList.style.display='none';bgWhite2.style.paddingBottom="0";}},onFileChange(e){varfiles=e.target.files||e.dataTransfer.filesif(!files.length)returnthis.createImage(files)},createImage(file){varvm=thisvarreader=nullvarleng=file.lengthfor(vari=0;i<leng;i++){reader=newwindow.FileReader()reader.readAsDataURL(file[i])reader.onload=function(e){vm.i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