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 an 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.