The buttons described in the section of Chapter 6 on the classic methods for registering event handlers:
But1 - Click Me! Uses: Codes the onclick handler directly in the button tag
But2 - Click Me! Uses: Codes the onclick handler as an anonymous function in the button tag
But3 - ClickMe! Uses: The handler is the result of a function defined elsewhere
But4 - ClickMe! Uses: The handler is a function defined elsewhere
But5 - ClickMe! Uses: The handler is a function expression defined elsewhere
But6 - ClickMe! Uses: Handler is added with addEventListener