problem with $().mouseover

problem with $().mouseover

Its my first simple JQUERY experience.
I try to implement something like this

Here is my HTML code:
  1. <html>
          <head>
              <script type="text/javascript" src="jquery-1.7.1.min.js"></script>
              <script type="text/javascript" src="jquery-1.7.1.js"></script>
              <script type="text/javascript" src="myJava.js"></script>
          </head>
          <body>
              <div id="main-menu">
                      <a href="#">link</a>
               </div>
          </body>
    </html>










And here is "myJava.js" code
  1. $('#main-menu a').mouseover(function() {
              alert("1");}
    );

When I press ALT + SHIFT + J in Firefox I have no error, whats wrong with my code?