jQuery: Using $.ajax() to post data

Got this from the server:

The jQuery Code START

    
    <script type="text/javascript" src="./jquery-1.5.1.js"></script>
    <script src="http://code.jquery.com/jquery-latest.js"></script>
    
    <script type="text/javascript">
      $(document).ready(function() {
        $.ajax( { type: "POST", url: "poster.php", data: {data: 1}, success: callback });
     });
     function callback(data, status) {
         $("div").text(data);
      }
    </script>
    
    <style type="text/CSS">
        <!--
        .code { color: red; }
        .back { background-color: yellow; }
        -->
   </style>
  </head>

  <body>
    <h1>jQuery: Using $.ajax() to post data</h1>
    Got this from the server: <div></div>