代码示例:(标识:jquery_ajax_ajaxsetup)
<html>
<head>
<script type="text/javascript" src="/jquery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
  $("button").click(function(){
    $.ajaxSetup({url:"/index/demo/ajax_load.html",success:function(result){
      $("div").html(result);}});
    $.ajax();
  });
});
</script>
</head>

<body>

<div id="txt"><h2>通过 AJAX 改变文本</h2></div>
<button>改变内容</button>

</body>
</html>
运行结果: