JavaScript 键盘事件监听与按键判断详解

JavaScript 键盘事件监听与按键判断详解

本文通过具体实例，讲解在 JavaScript 中获取并判断键盘按键的方法，供开发者参考。

在 Web 开发中，键盘事件的应用十分广泛。以下整理了键盘事件对应的键码（keyCode）供查阅。

keyCode 8 = BackSpace BackSpace
keyCode 9 = Tab Tab
keyCode 12 = Clear
keyCode 13 = Enter
keyCode 16 = Shift_L
keyCode 17 = Control_L
keyCode 18 = Alt_L
keyCode 19 = Pause
keyCode 20 = Caps_Lock
keyCode 27 = Escape Escape
keyCode 32 = space
keyCode 33 = Prior
keyCode 34 = Next
keyCode 35 = End
keyCode 36 = Home
keyCode 37 = Left
keyCode 38 = Up
keyCode 39 = Right
keyCode 40 = Down
keyCode 41 = Select
keyCode 42 = Print
keyCode 43 = Execute
keyCode 45 = Insert
keyCode 46 = Delete
keyCode 47 = Help
keyCode 48 = 0 equal braceright
keyCode 49 = 1 exclam onesuperior
keyCode 50 = 2 quotedbl twosuperior
keyCode 51 = 3 section threesuperior
keyCode 52 = 4 dollar
keyCode 53 = 5 percent
keyCode 54 = 6 ampersand
keyCode 55 = 7 slash braceleft
keyCode 56 = 8 parenleft bracketleft
keyCode 57 = 9 parenright bracketright
keyCode 65 = a A
keyCode 66 = b B
keyCode 67 = c C
keyCode 68 = d D
keyCode 69 = e E EuroSign
keyCode 70 = f F
keyCode 71 = g G
keyCode 72 = h H
keyCode 73 = i I
keyCode 74 = j J
keyCode 75 = k K
keyCode 76 = l L
keyCode 77 = m M mu
keyCode 78 = n N
keyCode 79 = o O
keyCode 80 = p P
keyCode 81 = q Q at
keyCode 82 = r R
keyCode 83 = s S
keyCode 84 = t T
keyCode 85 = u U
keyCode 86 = v V
keyCode 87 = w W
keyCode 88 = x X
keyCode 89 = y Y
keyCode 90 = z Z
keyCode 96 = KP_0 KP_0
keyCode 97 = KP_1 KP_1
keyCode 98 = KP_2 KP_2
keyCode 99 = KP_3 KP_3
keyCode 100 = KP_4 KP_4
keyCode 101 = KP_5 KP_5
keyCode 102 = KP_6 KP_6
keyCode 103 = KP_7 KP_7
keyCode 104 = KP_8 KP_8
keyCode 105 = KP_9 KP_9
keyCode 106 = KP_Multiply KP_Multiply
keyCode 107 = KP_Add KP_Add
keyCode 108 = KP_Separator KP_Separator
keyCode 109 = KP_Subtract KP_Subtract
keyCode 110 = KP_Decimal KP_Decimal
keyCode 111 = KP_Divide KP_Divide
keyCode 112 = F1
keyCode 113 = F2
keyCode 114 = F3
keyCode 115 = F4
keyCode 116 = F5
keyCode 117 = F6
keyCode 118 = F7
keyCode 119 = F8
keyCode 120 = F9
keyCode 121 = F10
keyCode 122 = F11
keyCode 123 = F12
keyCode 124 = F13
keyCode 125 = F14
keyCode 126 = F15
keyCode 127 = F16
keyCode 128 = F17
keyCode 129 = F18
keyCode 130 = F19
keyCode 131 = F20
keyCode 132 = F21
keyCode 133 = F22
keyCode 134 = F23
keyCode 135 = F24
keyCode 136 = Num_Lock
keyCode 137 = Scroll_Lock
keyCode 187 = acute grave
keyCode 188 = comma semicolon
keyCode 189 = minus underscore
keyCode 190 = period colon
keyCode 192 = numbersign apostrophe
keyCode 210 = plusminus hyphen macron
keyCode 211 =
keyCode 212 = copyright registered
keyCode 213 = guillemotleft guillemotright
keyCode 214 = masculine ordfeminine
keyCode 215 = ae AE
keyCode 216 = cent yen
keyCode 217 = questiondown exclamdown
keyCode 218 = onequarter onehalf threequarters
keyCode 220 = less greater bar
keyCode 221 = plus asterisk asciitilde
keyCode 227 = multiply division
keyCode 228 = acircumflex Acircumflex
keyCode 229 = ecircumflex Ecircumflex
keyCode 230 = icircumflex Icircumflex
keyCode 231 = ocircumflex Ocircumflex
keyCode 232 = ucircumflex Ucircumflex
keyCode 233 = ntilde Ntilde
keyCode 234 = yacute Yacute
keyCode 235 = oslash Ooblique
keyCode 236 = aring Aring
keyCode 237 = ccedilla Ccedilla
keyCode 238 = thorn THORN
keyCode 239 = eth ETH
keyCode 240 = diaeresis cedilla currency
keyCode 241 = agrave Agrave atilde Atilde
keyCode 242 = egrave Egrave
keyCode 243 = igrave Igrave
keyCode 244 = ograve Ograve otilde Otilde
keyCode 245 = ugrave Ugrave
keyCode 246 = adiaeresis Adiaeresis
keyCode 247 = ediaeresis Ediaeresis
keyCode 248 = idiaeresis Idiaeresis
keyCode 249 = odiaeresis Odiaeresis
keyCode 250 = udiaeresis Udiaeresis
keyCode 251 = ssharp question backslash
keyCode 252 = asciicircum degree
keyCode 253 = 3 sterling
keyCode 254 = Mode_switch

通过 keyCode 判断按键

可以通过 event 对象的 keyCode 属性来判断用户按下的是哪个键。

示例如下：

if(event.keyCode==13)alert("enter!");

以下是常见的键值对应表。

A　　0X65 　U 　　0X85
B　　0X66　 V　　 0X86
C　　0X67　 W　　 0X87
D　　0X68　 X 　　0X88
E　　0X69　 Y　　 0X89
F　　0X70　 Z　　 0X90
G　　0X71　 0　　 0X48
H　　0X72　 1　　 0X49
I　　0X73　 2　　 0X50
J　　0X74　 3 　　0X51
K　　0X75　 4 　　0X52
L　　0X76　 5 　　0X53
M　　0X77　 6　　 0X54
N　　0X78 　7 　　0X55
O　　0X79 　8 　　0X56
P　　0X80 　9 　　0X57
Q　　0X81　ESC　　0X1B
R　　0X82　CTRL 　0X11
S　　0X83　SHIFT　0X10
T　　0X84　ENTER　0XD

组合键检测逻辑

若需检测组合键，可判断是否同时按下了 Ctrl、Shift 或 Alt 键。例如，通过检查这些修饰键的状态，可以识别用户是否按下了特定的组合键。

以下是 JavaScript 获取键盘事件的通用写法。

<script type="text/javascript" language=JavaScript charset="UTF-8">
document.onkeydown=function(event){
  var e = event || window.event || arguments.callee.caller.arguments[0];
  if(e && e.keyCode==27){ // 按 Esc 
    //要做的事情
   }
  if(e && e.keyCode==113){ // 按 F2 
     //要做的事情
    }      
   if(e && e.keyCode==13){ // enter 键
     //要做的事情
  }
}; 
</script>

只要定义了相应的按键动作，当用户在浏览器中按下对应键时即可触发响应。该方案兼容目前所有主流浏览器。

关于 JS 判断键盘按键的具体实现。

window.document.onkeydown = disableRefresh;
function disableRefresh(evt){
evt = (evt) ? evt : window.event
if (evt.keyCode) {
  if(evt.keyCode == 116){
   //do something
  }
}
}

键码参考上述示例中的对应表。

同样利用 event 对象的 keyCode 属性来判断输入的键值。

示例如下：

if(event.keyCode==13){
var ieKey=event.keyCode;//获得键值，数字形式的
var realkey=String.fromCharCode(ieKey) //将数字形式的键值转化为真实的按键
alert(realkey);
}

键值对应表同上例所示。

希望本文所述内容能对大家的 JavaScript 程序设计有所帮助。