I get the usage definition of key events:

a) When the key is first pressed, the keydown event is sent. b) When the user releases the key, the keyup event is sent.

However, I am still confused about when to choose keydown event type that is appropriate over the keyup or vice versa in my code since when I pressed the ctrl key in both event types, they pretty much gave me the same result except as I realized that event.ctrlKey:true during keydown, and evet.ctrlkey: false during keyup. Would anyone please help me to give me a clear and definite usage of one over the other? Appreciate y'all!