Jquery not working at all =/

Jquery not working at all =/

I looked through a few threads but couldn't figure out why my script isn't working =/ I decided to test out something simple with Jquery before trying to build my portfolio. This is my script:
HTML
  2. <!DOCTYPE html>
  3. <html>
  4.     <head>
  5.         <title>Portfolio</title>
  6. <link rel='stylesheet' type='text/css' href='stylesheet.css'/>
  7.         <script type='text/javascript' src='script.js'></script>
  8.         
  9. </head>
  10. <body>
  11. <div class ="topbar"></div>
  12. </body>
  13. </html>
CSS

  3. .topbar {
  4.     height: 100px;
  5.     width: 100%;
  6.     border-radius: 5px;
  7.     background-color: #008800;
  8. }
Jscript
  2. $(document).ready(function() {
  3.     $('div').click(function() {
  4.         $(this).fadeOut('slow');
  5.     });
  6. });
I'm really unsure why this isn't working. I've tried a few other browsers (Mozilla, Opera etc...) and still not working.