Key code comparison table

1. keyCode is a numerical value associated with a specific keyboard key, provided by the browser when a keyboard event occurs.

2. When a user presses a key on the keyboard, JavaScript can access this keycode via the event object to determine which key was pressed.

3. Keycodes are typically used in the following JavaScript events:

(1) keydown event: Triggered when the user presses any key on the keyboard.

(2) `keyup` event: Triggered when the user releases a key on the keyboard.

4. KeyCode limitations: Case-insensitive, not restricted by keyboard layout, and function keys do not generate a KeyCode.

5. KeyCode may be deprecated in the future; alternative solutions should be used when working with KeyCode.