dojo/keys键盘按键

dojo/keys定义常用的键盘键值表，是常量。

简介：通常用法为：在按键事件中(onKeyDown(event))，可以获取到按键值(event.charOrCode)，通过dojo/keys判断是否为需要的按键。

属性：

BACKSPACE: 8,
TAB: 9,
CLEAR: 12,
ENTER: 13,
SHIFT: 16,
CTRL: 17,
ALT: 18,
META: has("webkit") ? 91 : 224,        // the apple key on macs
PAUSE: 19,
CAPS_LOCK: 20,
ESCAPE: 27,
SPACE: 32,
PAGE_UP: 33,
PAGE_DOWN: 34,
END: 35,
HOME: 36,
LEFT_ARROW: 37,
UP_ARROW: 38,
RIGHT_ARROW: 39,
DOWN_ARROW: 40,
INSERT: 45,
DELETE: 46,
HELP: 47,
LEFT_WINDOW: 91,
RIGHT_WINDOW: 92,
SELECT: 93,
NUMPAD_0: 96,
NUMPAD_1: 97,
NUMPAD_2: 98,
NUMPAD_3: 99,
NUMPAD_4: 100,
NUMPAD_5: 101,
NUMPAD_6: 102,
NUMPAD_7: 103,
NUMPAD_8: 104,
NUMPAD_9: 105,
NUMPAD_MULTIPLY: 106,
NUMPAD_PLUS: 107,
NUMPAD_ENTER: 108,
NUMPAD_MINUS: 109,
NUMPAD_PERIOD: 110,
NUMPAD_DIVIDE: 111,
F1: 112,
F2: 113,
F3: 114,
F4: 115,
F5: 116,
F6: 117,
F7: 118,
F8: 119,
F9: 120,
F10: 121,
F11: 122,
F12: 123,
F13: 124,
F14: 125,
F15: 126,
NUM_LOCK: 144,
SCROLL_LOCK: 145,
UP_DPAD: 175,
DOWN_DPAD: 176,
LEFT_DPAD: 177,
RIGHT_DPAD: 178,

使用方法：

switch(charOrCode){
      case keys.LEFT_ARROW:
      case keys.UP_ARROW:
      case keys.DOWN_ARROW:
      case keys.RIGHT_ARROW:
        output = "You pressed an arrow key";
        break;
      case keys.BACKSPACE:
        output = "You pressed the backspace";
        break;
      case keys.TAB:
        output = "You pressed the tab key";
        break;
      case keys.ESCAPE:
        output = "You pressed the escape key";
        break;
      default:
        output = "You pressed some other key";
    }