ngKeydown/ngKeypress/ngKeyup
该指令在按键按下/按键按下/按键松开时执行指定表达式。
ngKeydown和ngKeypress略有不同，目前的测试是ngKeypress针对系统按键是无效的，而ngKeydown可以。
ngKeyup指令在按键松开的时候执行。
使用代码：

  <input ng-keydown="count = count + 1" ng-init="count=0">{{count}}
  <input ng-keypress="count = count + 1" ng-init="count=0">{{count}}
  <input ng-keyup="count = count + 1" ng-init="count=0">{{count}}

ngMousedown/ngMouseenter/ngMouseleave/ngMousemove/ngMouSEOver/ngMouseup

该指令在鼠标按下/鼠标进入/鼠标离开/鼠标移动/鼠标在上面/鼠标松开时执行指定表达式。

使用代码：

  <button ng-mousedown="count = count + 1" ng-init="count=0">on mouse down</button>{{count}}
  <button ng-mouseenter="count = count + 1" ng-init="count=0">when mouse enter</button>{{count}}
  <button ng-mouseleave="count = count + 1" ng-init="count=0">when mouse leave</button>{{count}}
  <button ng-mousemove="count = count + 1" ng-init="count=0">when mouse move</button>{{count}}
  <button ng-mouSEOver="count = count + 1" ng-init="count=0">when mouse is over</button>{{count}}
  <button ng-mouseup="count = count + 1" ng-init="count=0">on mouse up</button>{{count}}