MouseEvent.altKey 只读属性是一个Boolean变量。当事件触发时，如果alt 被按下，则返回 true，否则返回false。
语法
var altKeyPressed = instanceOfMouseEvent.altKey
示例
<html>
<head>
<title>altKey example</title>
<script type="text/javascript">
function showChar(e){
alert(
"Key Pressed: " + String.fromCharCode(e.charCode) + "\n"
+ "charCode: " + e.charCode + "\n"
+ "ALT key pressed: " + e.altKey + "\n"
);
}
</script>
</head>
<body onkeypress="showChar(event);">
<p>
Press any character key,
with or without holding down the ALT key.<br />
You can also use the SHIFT key together with the ALT key.
</p>
</body>
</html>
规范
| Specification | Status | Comment |
|---|---|---|
| Document Object Model (DOM) Level 3 Events Specification MouseEvent.altkey |
Working Draft | No change from Document Object Model (DOM) Level 2 Events Specification. |
| Document Object Model (DOM) Level 2 Events Specification MouseEvent.altkey |
Recommendation | Initial definition. |
浏览器兼容性
| Feature | Firefox (Gecko) | Chrome | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
| Feature | Firefox Mobile (Gecko) | Android | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|
| Basic support | ? | ? | ? | ? | ? |