Why certain text doesn't display

Why certain text doesn't display

Obviously, new to Jquery. Here's the file:

  1. <html>
  2.   <head>
  3.     <script type='text/javascript' src='jquery-1.9.1.js'></script>
  4.  
  5.     <script type='text/javascript'>
  6. if ($) {
  7.   $(document).ready(
  8.     function() {
  9.       $('p').addClass('Loaded');
  10.       $('p').text('jQuery loaded and running!');
  11.     }
  12.   );
  13. }    
  14.     </script>
  15.     <style type='text/css'>
  16. p.Loaded {
  17.     color: green;
  18.     border: 1px solid green;
  19. }    
  20.     </style>
  21.   </head>
  22.   <body>
  23.     <p>
  24.         jQuery is not loaded.
  25.     </p>
  26.   </body>
  27. </html>

(from a web site  http://www.java2s.com). So, the text jquery is loaded and running does appear at the top of the browser window in a long box the width of the window and it's not green and also other text does not appear. Why?

MUCH THANKS.

RON