Javascript detection keyboard key information and key code value correspondence Introduction _javascript Skill

JavaScript has 3 event handles in the input state of the corresponding keyboard: KeyDown, KeyPress, and KeyUp.
The corresponding meaning is: The key is pressed (press the button but has not been lifted), click the button (press and lift the button), press the key to lift (after the key)
Classification of keys
Keys can be divided into "real" and "virtual"
Real key can be understood as we can see and print out the keys, such as the letter "A", the number "1", the character "?" Wait a minute
Virtual keys are those buttons that can't be printed to control, such as Ctrl, ALT, Shift, arrow keys, and so on.
IE has a special case when dealing with a virtual key: a virtual key does not produce a KeyPress event and must be captured using KeyDown or KeyUp
key code and character code
Key code is the computer to identify the different keys of the code, each button has a key code
The character code is unique to the actual key that can be printed, corresponding to the characters displayed on the keyboard
Key codes can be converted to character codes using String.fromCharCode ()
The key code and the corresponding table for the character code can be found at the end of this article.
Get real Key

Copy Code code as follows:

function getKeyCode (e) {
var keycode = 0;
var e = e | | window.event;
keycode = E.keycode | | E.which | | E.charcode;
alert (keycode);
}

Explain it a little bit.
1. E for Firefox and other standard browser support JS hidden variables, indicating an "event", IE series does not "E", but with window.event to represent "event"; so var e = e | | Window.event: Gets the event that is currently occurring.
2. E.keycode, E.which, E.charcode are all on behalf of the key code, but different browsers support different wording
Get Virtual Key

Copy Code code as follows:

function getKeyCode (e) {
var keycode = 0;
var e = e | | window.event;
if (e.ctrlkey) alert ("Ctrlkey pressed");
if (e.altkey) alert ("Altkey pressed");
if (e.shiftkey) alert ("Shiftkey pressed");
}

Key code values for letters and numeric keys (keycode)
Keys	Key code	Keys	Key code	Keys	Key code	Keys	Key code
A	65	J	74	S	83	1	49
B	66	K	75	T	84	2	50
C	67	L	76	U	85	3	51
D	68	M	77	V	86	4	52
E	69	N	78	W	87	5	53
F	70	O	79	X	88	6	54
G	71	P	80	Y	89	7	55
H	72	Q	81	Z	90	8	56
I	73	R	82	0	48	9	57

　　

Key code values for keys on the numeric keypad (keycode)				Function key key code value (KeyCode)
Keys	Key code	Keys	Key code	Keys	Key code	Keys	Key code
0	96	8	104	F1	112	F7	118
1	97	9	105	F2	113	F8	119
2	98	*	106	F3	114	F9	120
3	99	+	107	F4	115	F10	121
4	100	Enter	108	F5	116	F11	122
5	101	-	109	F6	117	F12	123
6	102	.	110
7	103	/	111

　　

Control key key code value (KeyCode)
Keys	Key code	Keys	Key code	Keys	Key code	Keys	Key code
BackSpace	8	Esc	27	Right Arrow	39	-_	189
Tab	9	Spacebar	32	Dw Arrow	40	.>	190
Clear	12	Page up	33	Insert	45	/?	191
Enter	13	Page down	34	Delete	46	`~	192
Shift	16	End	35	Num Lock	144	[{	219
Control	17	Home	36	;:	186	\|	220
Alt	18	Left Arrow	37	=+	187	]}	221
Cape Lock	20	Up Arrow	38	,<	188	'"	222

Multimedia key code value (KeyCode)
Keys	Key code	Keys	Key code	Keys	Key code	Keys	Key code
Volume Plus	175
Volume reduction	174
Stop it	179
Mute	173
Browser	172
Mail	180
Search	170
Collection	171