JavaScript图片库实现与DOM节点属性详解

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript" src="js/showPic.js"></script>
    <link rel="stylesheet" type="text/css" href="css/layout.css" rel="external nofollow" />
  </head>
  <body>
    <h1>Snapshots</h1>
    <ul>
      <li>
        <a href="img/a.jpg" rel="external nofollow" title="Hongse Fengye" onclick="showPic(this);return false;">红色枫叶</a>
      </li>
      <li>
        <a href="img/b.jpg" rel="external nofollow" title="Huangse Fengye" onclick="showPic(this); return false;">黄色枫叶</a>
      </li>
      <li>
        <a href="img/c.jpg" rel="external nofollow" title="Hongse Shu" onclick="showPic(this); return false;">红色树</a>
      </li>
      <li>
        <a href="img/d.jpg" rel="external nofollow" title="Lanse Fengye" onclick="showPic(this);return false;">蓝色枫叶</a>
      </li>
    </ul>
    <img src="img/3302-106.jpg" id="placeholder" alt="My Gallery"/>
    <p id="description">Choose an image</p>
  </body>
</html>

function showPic(whichpic){
  var sorce=whichpic.getAttribute("href");
  var placeholder=document.getElementById("placeholder");
  placeholder.setAttribute("src",sorce);
  var text=whichpic.getAttribute("title");
  var description=document.getElementById("description");
  description.firstChild.nodeValue=text;
}

img{
  width: 600px;
}
body{
  font-family: helvetica,arial,serif;
  color: #333;
  background-color: #ccc;
  margin: 1em 10%;
}
h1{
  color:#333;
  background-color: transparent;
}
a{
  color: #c60;
  background-color: transparent;
  font-weight: bold;
  text-decoration: none;
}
ul{
  padding: 0;
}
li{
  float: left;
  padding: 1em;
  list-style: none;
}
img{
  display: block;
  clear: both;
}

document.body.childNodes;

document.body.nodeType;