为什么这段代码是先执行alert("i'm "+this.className);求指导，谢谢

为什么这段代码是先执行alert("i'm "+this.className);再执行this.style.backgroundColor="yellow";我想要的效果是先背景改变，再跳出alert，点确认后又变回原来的背景，求指导，谢谢

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
<title>Document</title>
<style>
  *{
   padding: 0;
   margin: 0;
  }
  .id1
  {
   position: absolute;
   background-color: red;
   width: 200px;
   height: 200px;
   z-index: -1;
  }
  .id2
  {
   position: absolute;
   background-color: blue;
   width: 150px;
   height: 150px;
   top: 25px;
   left: 25px;
  }
  .id3
  {
   position: absolute;
   background-color: green;
   width: 100px;
   height: 100px;
   top: 25px;
   left: 25px;
  }
</style>
<script>
  function lightHight() {
   this.style.backgroundColor="yellow";
   alert("i'm "+this.className);
   this.style.backgroundColor="";

   // body...
  }
  window.onload=function(){
   var divs=document.getElementsByTagName("div");
   divs[0].addEventListener("click",lightHight);
   divs[1].addEventListener("click",lightHight);
   divs[2].addEventListener("click",lightHight);
  } </script>
</head>
<body>
<div>

  <div>

   <div>

   </div>
  </div>
</div>
</body>
</html>

慕粉3834220

浏览 1798回答 2

2回答

lkepanda

我也是背景颜色出不来

0 0

guoyou

效果确实是先背景改变，再跳出alert，点确认后又变回原来的背景并没有问题

0 1

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