JavaScript通过行内样式动态切换背景图片

<!DOCTYPE html>
<html>
 <head>
 <meta charset="utf-8">
 <title>更换背景</title>
 <style type="text/css">
  *{
  margin: 0;
  padding: 0;
  }
  body{
  background: url(./images/01.jpg) no-repeat;
  background-size: 600px;
  }
  ul{
  list-style: none;
  }
  ul li{
  width: 80px;
  height: 50px;
  border: 1px solid #222;
  float: left;
  margin: 10px;
  }
  ul li img{
  width: 80px;
  height: 50px;
  cursor: pointer;
  }
 </style>
 <script type="text/javascript">
  window.onload = function(){
  var imgs = document.getElementsByTagName("img");
  for (var i = 0; i < imgs.length; i++) {
   imgs[i].onclick = function(){
   document.body.style.background = "url("+this.src+") no-repeat";//通过js控制改变行内样式
   document.body.style.backgroundSize = "600px";
   }
  }
  }
 </script>
 </head>
 <body>
 <ul>
  <li><img src="./images/01.jpg" ></li>
  <li><img src="./images/02.jpg" ></li>
  <li><img src="./images/03.jpg" ></li>
 </ul>
 </body>
</html>