Hello World, Revisited
This example revisits our original Hello World example to show how you can easily
change a postback-based form and interactions into AJAX-postback based ones.
Whereas before, we executed a Server on the button's click, we have now changed
that to a Ajax. Everything else remains the same.
The result is the exact same interaction, but now performed Asynchronously via Ajax. Note
that after clicking the button, the entire page doesn't "refresh" -- but the label's content
changes as defined in the PHP method btnButton_Click.