​x
 
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
  $("a").click(function(event){
    event.preventDefault();
    alert("Default prevented: " + event.isDefaultPrevented());
  });
});
</script>
</head>
<body>
<a href="http://w3school.com.cn/">W3School</a>
<p>preventDefault() 方法将防止上面的链接打开 URL。</p>
<p>请点击该链接，检查是否阻止了默认动作。</p>
</body>
</html>
​