Here is google’s hello world code for v3:
http://code.google.com/apis/maps/documentation/javascript/tutorial.html#HelloWorld
this loads and displays the map just fine. However, once I add any code within the script tags, the map no longer displays. For example
if I just declare a class immediately after initialize(), the map no longer displays.
Here is an example:
http://hollaballoon.com/test/test.html
Please download the source and try for yourself. How can this be solved?
You might want to think about using a javascript debugger to help you develop. The code you added after the google maps stuff has some syntax problems. Firefox has a great add-on called Firebug, and Chrome/Safari both have built in debuggers.
Having said that, you might try changing your code to this instead: