displaying json data

displaying json data

i am  a newbie and am stuck at retrieving json data.

following is my index.php :

  1. <script type="text/javascript" src="jquery-1.3.2.min_2.js">
  2.     $("document").ready(function() {
  3.        
  4.         $.getJSON("data.php",function(jsondata){
  5.         $("#content").html(jsondata[0].content);   
  6.            
  7.         });
  8.     });
  9. </script>
  10. </head>
  11. <body>
  12. <div id="content"></div>
  13. <div class="lg"></div>
  14. </body>

in my data.php i am using the standard way of encoding and sending the data:
  1. echo json_encode($jsondata);
i am using mysql database.
when i open localhost/data.php the json data is shown on the browser.
but in case of index.php i donot get any desired output.
Please explain.
Thanks!