js扑捉键盘对应的keycode

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 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