Question

JavaScript 获取keycode问题，问题如下

function keyUp(e) {
var e=e || event;
var currKey=e.keyCode;
var keyName = String.fromCharCode(currKey);
if(currKey == 96) keyName = 0;
if(currKey == 97) keyName = 1;
if(currKey == 98) keyName = 2;
if(currKey == 99) keyName = 3;
if(currKey == 100) keyName = 4;
if(currKey == 101) keyName = 5;
if(currKey == 102) keyName = 6;
if(currKey == 103) keyName = 7;
if(currKey == 104) keyName = 8;
if(currKey == 105) keyName = 9;
if(currKey == 106) keyName = "*";
document.getElementById("key").innerHTML = "按键码: " + currKey+ " 字符: " + keyName;

}
document.onkeyup = keyUp;//当键盘松开时

<div id="key" style="color:red;"></div>

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1.var e=e || event;是什么意思
2. var currKey=e.keyCode;是什么意思

Answer 1

var e=e || event 这个是为了处理IE兼容性的，IE事件和标准有些不同，没有e，但是它用的是window.event

e.keyCode 取的是你按的哪个键，是有个编号的，如回车是13

Answer 2

1 var e=e || event;
e不为false或null或0或空字符串时,e取event值
e为false或null或0或空字符串时,e取e值

2.var currKey=e.keyCode 获得传入参数的 keyCode 值

追问

e跟event有什么区别

追答

你的event在哪里定义的？ 代码敲上、