js键盘上下左右方向键触发function的示例代码

/**
* 如何使用键盘上下左右方向键触发function呢？
* 简单示例，技巧呈现
* 编辑：教程集 www.jiaochengji.com
*/
<script type="text/javascript">
 function jumpPage() {
    if (event.keyCode==37)//左
fun_a();
if (event.keyCode==38)//上
 fun_b();
 if (event.keyCode==39)//右
fun_c();
if (event.keyCode==40)//下
fun_d();
 }
 
function fun_a(){
window.alert('你按下了左')
 }

function fun_b(){
window.alert('你按下了上')
}

function fun_c(){
window.alert('你按下了右')
}

function fun_d(){
 window.alert('你按下了下')
}
document.onkeydown=jumpPage;
</script>

<table width="100%" border="1" cellspacing="1" cellpadding="0" id=table>
<tr id="lineone" style="background-color:#00cccc;">
<td id=aa height="23">&nbsp;</td>
<td id=aa >按向下键</td>
<td id=cc >按向下键</td>
<td id=dd >按向下键</td>
<td id=ee >按向下键</td> </tr>
<tr id="linetwo" tyle="background-color:#ffffff;">
<td id=a height="23">&nbsp;</td>
<td id=b >按向上键</td>
<td id=c >按向上键</td>
<td id=d >按向上键</td>
<td id=e >按向上键</td> </tr>
</table>
<script language="javascript">
function keyDown(e) {
var iekey=event.keyCode;
action(iekey); }
document.onkeydown = keyDown;

function action(iekey) {
if(iekey==40) {
lineone.style.backgroundColor = "";
linetwo.style.backgroundColor = "#00cccc";
}

if(iekey==38) {
lineone.style.backgroundColor = "#00cccc";
linetwo.style.backgroundColor = ""; } }
</script>

<input name="id" type="hidden" id="id" value="1" />