keydown Event: This event occurs when the user has pressed down the key. It will occur even if the key pressed does not produce a character value.
keypress Event: This event occurs when the user presses a key that produces a character value. These include keys such as the alphabetic, numeric, and punctuation keys. Modifier keys such as ‘Shift’, ‘CapsLock’, ‘Ctrl’ etc. do not produce a character, therefore they have no ‘keypress’ event attached to them.
keyup Event: This event occurs when the user has released the key. It will occur even if the key released does not produce a character value.