关于程序中设置了按键控制却没有反应的问题

Question

document.onkeypress = KeyPressHandle;
function KeyPressHandle(keyEvent)
{
keyEvent=keyEvent?keyEvent:window.event;
       var keyvalue=keyEvent.which?keyEvent.which:keyEvent.keyCode;
switch(keyvalue)
{
  case 37:
case 38:
onClickUp();
break;
case 13:
case 39:
case 40:
onClickDown();
break;
}
}
通过这个函数我希望在我按向上和向左两个键的时候，实现onClickUp（）这个函数，按回车、向右和向下三个键的时候，实现onClickDown()这个函数，不知道为什么，这样写出来的代码在运行后按键一点都木有反应，谁来帮帮我吧，谢谢啦

Answer 1

onkeypress不对某些键响应<script>
document.onkeydown = KeyPressHandle;
    function KeyPressHandle(keyEvent)
    {
        keyEvent=keyEvent?keyEvent:window.event;
              var keyvalue=keyEvent.which?keyEvent.which:keyEvent.keyCode;
        switch(keyvalue)
        {
         case 37:    
        case 38:
            onClickUp();
            break;
        case 13:
        case 39:
        case 40:
            onClickDown();
            break;
        }
    }
onClickUp = function(){alert("onClickUp");};
onClickDown = function(){alert("onClickDown");};
</script>

Answer 2

http://blog.csdn.net/lsgis2001/article/details/2147905