Uncaught ReferenceError: $ is not defined error in jQuery
Change the order you're including your scripts (jQuery first):
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<script type="text/javascript" src="./javascript.js"></script>
<script
src="http://maps.googleapis.com/maps/api/js?key=YOUR_APIKEY&sensor=false">
</script>
Include the jQuery file first:
<script src="http://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<script type="text/javascript" src="./javascript.js"></script>
<script
src="http://maps.googleapis.com/maps/api/js?key=AIzaSyCJnj2nWoM86eU8Bq2G4lSNz3udIkZT4YY&sensor=false">
</script>