简单隔行变色及添加删除

<div>
        <label for="">姓名：label>
        <input type="text" id="thename">
        <label for="">年龄label>
        <input type="text" id="theage">
        <label for="">学期label>
        <select name="" id="thexue">
            <option value="p1">p1option>
            <option value="p2">p2option>
            <option value="p3">p3option>
            <option value="p4">p4option>
            <option value="p5">p5option>
            <option value="p6">p6option>
        select>
        <button onclick="addFun()">添加button>
        <button onclick="openFun()" id="acolor">开启隔行变色button>
    div>
    <table border="1" cellpadding=0 cellspacing=0>
        <thead>
            <tr>
                <th>序号th>
                <th>姓名th>
                <th>年龄th>
                <th>学期th>
                <th>操作th>
            tr>
        thead>
        <tbody id="thebody">
            
        tbody>
    table>

var thename=document.getElementById("thename")
        var thegae=document.getElementById("theage")
        var thexue=document.getElementById("thexue")
        var thebody=document.getElementById("thebody")
        var acolor=document.getElementById("acolor")
        var arr = [
	   	  {
     id:1,name:'liujie',age:32,xue:'p2'},
	   	  {
     id:2,name:'liujie1',age:32,xue:'p3'},
	   	  {
     id:3,name:'liujie2',age:32,xue:'p4'}
       ]
       getlou()
        showFun()
       function showFun(){
     
           thebody.innerHTML=""
           var lss=""
           arr.forEach(function(item,index){
     
               lss+=`
                ${
       index+1}
                ${
       item.name}
                ${
       item.age}
                ${
       item.xue}
                ${
       item.id})">删除
            
               `
           })
           thebody.innerHTML=lss
       }
       //添加
       function addFun(){
     
           if(thename.value==""&&theage.value==""){
     
               alert("名字跟年龄不能是空")
               return
           }
           var obj={
     }
           obj.id=new Date().getTime()
           obj.name=thename.value
           obj.age=theage.value
           obj.xue=thexue.value
           arr.push(obj)
           showFun()
           setlou(arr)
       }
       //删除
       function delFun(id){
     
          arr.forEach(function(item,index){
     
              if(id==item.id){
     
                  arr.splice(index,1)
              }
          })
          showFun()
          setlou(arr)
       }
       //隔行换色
       var sure=true
       function openFun(){
     
           var trs=document.querySelectorAll("tbody>tr")
           if(sure){
     
               for(let i=0;i<trs.length;i++){
     
                   if(i%2==0){
     
                    acolor.innerHTML="关闭隔行换色"
                    trs[i].style.background="orange"
                   }else{
     
                       trs[i].style.background="green"
                   }
               }sure=false
           }else{
     
               for(let j=0;j<trs.length;j++){
     
                   acolor.innerHTML="开启隔行变色"
                   trs[j].removeAttribute("style")
                    sure=true
               }
           }

       }

       //存
       function setlou(arr){
     
           localStorage.setItem("myarr",JSON.stringify(arr))
       }

       //取
       function getlou(){
     
           var str=localStorage.getItem("myarr")
           if(str==null){
     
               arr=[]
               return
           }
           arr=JSON.parse(str)
       }