e.metaKey 在 JavaScript MouseEvent 中指的是哪个键？
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Which key does the e.metaKey refer to in JavaScript MouseEvent?
提问by Pacerier
MouseEvent.metaKeydoesn't seem to work. On both FireFox and Chrome, it returns falseeven if I hold the Winkey while clicking:
MouseEvent.metaKey似乎不起作用。在 FireFox 和 Chrome 上，false即使我Win在单击时按住键，它也会返回：
<!doctype html>
<button onclick=alert(event.metaKey)>click while holding "meta key"</button>MDN states:
MDN状态：
The
MouseEvent.metaKeyread-only property returning aBooleanthat indicates if the Metakey was pressed (true) or not (false) when the event occured.Note: On Macintosh keyboards, this is the command key (?). On Windows keyboards, this is the windows key (?).
Browser Compatibility
该
MouseEvent.metaKey只读属性返回Boolean表示如果Meta按下键（true）否（false）时发生了此事件。注意：在 Macintosh 键盘上，这是命令键 ( ?)。在 Windows 键盘上，这是 Windows 键 ( ?)。
浏览器兼容性
MDN claims MouseEvent.metaKeyis supported on FireFox and Chrome, but it's not working.
MouseEvent.metaKeyFireFox 和 Chrome 支持MDN 声明，但它不起作用。
Which key does MouseEvent.metaKeyrefer to?
MouseEvent.metaKey指的是哪个键 ？
Why is the above code not working?
为什么上面的代码不起作用？
回答by nnnnnn
If you're asking which key you would have to press on a Windows system in order for the MouseEvent's metaKeyproperty to be true, the answer is that it depends on the browser. And some Windows browsers simply don't support it and always return falseor undefined.
如果您要问在 Windows 系统上必须按哪个键才能使MouseEvent'smetaKey属性成为true，答案是这取决于浏览器。并且一些 Windows 浏览器根本不支持它并且总是返回falseor undefined。
I could not find an up-to-date chart of browser support for metaKey, though there is a really old one at QuirksMode.org.
我找不到浏览器支持的最新图表metaKey，尽管在 QuirksMode.org 上有一个非常古老的图表。
If you are using jQuery, metaKeyis one of the event properties that it normalizes for cross-browser compatibility.
如果您使用的是 jQuery，它metaKey是为跨浏览器兼容性而标准化的事件属性之一。
If you need to implement a key + mouse event for some functionality on your website, I would use the Shiftkey, so that it works on all systems. (If you need more than one key option, I would suggest you rethink your design.)
如果您需要为网站上的某些功能实现键 + 鼠标事件，我会使用该Shift键，以便它适用于所有系统。（如果您需要多个关键选项，我建议您重新考虑您的设计。）
回答by Orwellophile
Empirical testing, shows the following results. Not that jQuery doesn't do a terribly good job of normalizing ^F.
经验测试，显示以下结果。并不是说 jQuery 在规范化 ^F 方面做得不好。
On a Mac, in Safari Version 5.1.7 & 6.0.
在 Mac 上，在 Safari 版本 5.1.7 和 6.0 中。
F Keypress: 102, 102
?F Keypress: 102, 102 meta
?F Keypress: 402, 402 alt
?F Keypress: 6, 6 ctrl
?F Keypress: 70, 70 shift
On a Mac, in Firefox 15.0.1:
在 Mac 上，在 Firefox 15.0.1 中：
F Keypress: 102, 0
?F Keypress: 102, 0 meta
?F Keypress: 402, 0 alt
?F Keypress: 102, 0 ctrl
?F Keypress: 70, 0 shift
On a Mac, in Google Chrome 18.0.1024.168:
在 Mac 上，在 Google Chrome 18.0.1024.168 中：
F Keypress: 102, 102
?F (No triggers sent for ? + key)
?F Keypress: 402, 402 alt
?F Keypress: 6, 6 ctrl
?F Keypress: 70, 70 shift
Test code: // jquery-1.7.2
测试代码：// jquery-1.7.2
$(document.defaultView).keypress(function(e) {
console.log("Keypress: " + e.which + ", " + e.keyCode, " "
+ (e.metaKey ? "meta " : "")
+ (e.ctrlKey ? "ctrl " : "")
+ (e.altKey ? "alt " : "")
+ (e.shiftKey ? "shift " : ""));
});
回答by user10089632
Which key does MouseEvent.metaKey refer to?
MouseEvent.metaKey 指的是哪个键？
It refers to the windows key 
它指的是windows键
Why is the above code not working?
为什么上面的代码不起作用？
Because of a bugas of at least Firefox 48, see the docsfor more infos.
由于至少在 Firefox 48中存在错误，请参阅文档以获取更多信息。
A solution :
一个解法 ：
Use the shiftKeyinstead. Which has a property with the same name on the event object.
使用shiftKey来代替。它在事件对象上有一个同名的属性。
