There are three event on the document keyboard onkeypress onkeydown onkeyup each will return a keycode in integer.

keypressed keyvaluecounter on hold down

 Here is the list of the number of the keyboard below and scroll down more for coding

key pressed	key code		key pressed	key code		key pressed	key code		A-Z key press	key code
BACKSPACE	8		SPACE	32		1	97		a	65
Tab	9		page up	33		2	98		b	66
Enter	13		page down	34		3	99		c	67
SHIFT	16		end	35		4	100		d	68
CTRL	17		home	36		5	101		e	69
ALT	18		left-arrow	37		6	102		f	70
Pause	19		up-arrow	38		7	103		g	71
Cap lock	20		right-arrow	39		8	104		h	72
			down-arrow	40		9	105		i	73
ESC	27					*	106		j	74
			insert	45		+	107		k	75
numlock	144		delete	46					l	76
Scroll Lock	145					minus	109		m	77
' "	222		0!	48		decimal	110		n	78
[ {	219		1@	49		divide	111		o	79
] }	221		2#	50		F1	112		p	80
\ |	220		3$	51		F2	113		q	81
; :	186		4%	52		F3	114		r	82
= +	187		5^	53		F4	115		s	83
, <	188		6&	54		F5	116		t	84
- _	189		7*	55		F6	117		u	85
/ ?	190		8(	56		F7	118		v	86
. >	191		9)	57		F8	119		w	87
` ~	192					F9	120		x	88
						F10	121		y	89
						F11	122		z	90
						F12	123