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JavaScript 的事件冒泡 demo

程序员文章站 2024-03-20 20:08:34
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如果你还不理解JavaScript的事件冒泡往下看:

 

<!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" lang="zh" xml:lang="zh">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="developer" content="Realazy" />
<title>Bubble in JavaScript DOM</title>
<style type="text/css" media="screen">
 div * {display:block; margin:4px; padding:4px; border:1px solid white;}
 textarea {width:20em; height:2em;}
</style>
<script type="text/javascript">
    //<![CDATA[
    function init(){
  var log = document.getElementsByTagName('textarea')[0];
  var all = document.getElementsByTagName('div')[0].getElementsByTagName('*');
  for (var i = 0, n = all.length; i < n; ++i){
   all[i].onmouseover = function(e){
    this.style.border = '1px solid red';

    log.value = '鼠标现在进入的是: ' + this.nodeName;
   };
   all[i].onmouseout = function(e){
    this.style.border = '1px solid white';
   };
  }

  var all2 = document.getElementsByTagName('div')[1].getElementsByTagName('*');
  for (var i = 0, n = all2.length; i < n; ++i){
   all2[i].onmouseover = function(e){
    this.style.border = '1px solid red';

    if (e) //停止事件冒泡
     e.stopPropagation();
    else
     window.event.cancelBubble = true;
    
    log.value = '鼠标现在进入的是: ' + this.nodeName;
   };
   all2[i].onmouseout = function(e){
    this.style.border = '1px solid white';
   };
  }
 }
 window.onload = init;
    //]]>
</script>
</head>
<body>
<h1>Bubble in JavaScript DOM</h1>
<p>DOM树的结构是:</p>
<pre><code>
UL
  - LI
     - A
   - SPAN
</code></pre>
<div>
 <ul>
  <li><a href="#"><span>Bubbllllllllllllllle</span></a></li>
  <li><a href="#"><span>Bubbllllllllllllllle</span></a></li>
 </ul>
</div>
<textarea></textarea>
<p>鼠标进入UL的任何一个子元素,如果不停止冒泡,我们从UL到SPAN都定义了鼠标悬停(<code>mouseover</code>)事件,这个事件会上升了UL,从而从鼠标所进入的元素到UL元素都会有红色的边。</p>
<div>
 <ul>
  <li><a href="#"><span>Bubbllllllllllllllle</span></a></li>
  <li><a href="#"><span>Bubbllllllllllllllle</span></a></li>
 </ul>
</div>
<p>如果停止冒泡,事件不会上升,我们就可以获取精确的鼠标进入元素。</p>
</body>
</html>

 原文地址:http://www.blueidea.com/tech/web/2007/4628.asp