It seems to me, either your scripts are not found or it's perhaps an encoding issue.
Are you sure that both your scripts are loaded? Because your code works for me here on Safari. NOTE: Please always refer to your browser type and version for such issues.
And you have a document encoding mismatch between your document (set as charset=ISO-8859-1) and your scripts and css (set a utf-8) which could cause problems. Make them both utf-8.
As long both of these things are sound, your example should work.