To answer this question, we need to understand the difference between the key-down, key-press, and key-up events in JavaScript.
The key-down event is triggered when a key on the keyboard is pressed down. The key-press event is triggered when a key is pressed and released. The key-up event is triggered when a key is released.
Now let's go through each option to understand why it is correct or incorrect:
Option A) If onKeyDown returns false, the key-press event is cancelled.
This option is incorrect. The onKeyDown event does not cancel the key-press event. The onKeyDown event is triggered before the key-press event and can be used to prevent the default behavior of the key-press event, but it does not cancel it.
Option B) If onKeyPress returns false, the key-down event is cancelled.
This option is incorrect. The onKeyPress event does not cancel the key-down event. The onKeyPress event is triggered after the key-down event and can be used to prevent the default behavior of the key-down event, but it does not cancel it.
Option C) If onKeyDown returns false, the key-up event is cancelled.
This option is incorrect. The onKeyDown event does not cancel the key-up event. The onKeyDown event is triggered before the key-up event and can be used to prevent the default behavior of the key-up event, but it does not cancel it.
Option D) If onKeyPress returns false, the key-up event is canceled.
This option is incorrect. The onKeyPress event does not cancel the key-up event. The onKeyPress event is triggered after the key-up event and can be used to prevent the default behavior of the key-up event, but it does not cancel it.
Therefore, the correct answer is A) If onKeyDown returns false, the key-press event is cancelled. This option is correct because returning false from the onKeyDown event will prevent the key-press event from being triggered.