var element = //the DOM element to listen for the key on.
element.onkeyup = function(e) {
   if(e.metaKey) {
      //command key was pressed
   }
}

对于使用jQuery的人，有一个很好的插件来处理关键事件:

GitHub上的jQuery热键

对于捕获⌘+S和Ctrl+S，我使用这个:

$(window).bind('keydown.ctrl_s keydown.meta_s', function(event) {
    event.preventDefault();
    // Do something here
});

基于Ilya的数据，我编写了一个香草JS库，用于在Mac上支持修改器键:https://github.com/MichaelZelensky/jsLibraries/blob/master/macKeys.js

就像这样用吧，例如:

document.onclick = function (event) {
  if (event.shiftKey || macKeys.shiftKey) {
    //do something interesting
  }
}

在Chrome, Safari, Firefox, Mac上的Opera上进行了测试。请检查是否适合您。

keyCode和现在已弃用，因此建议避免在这里使用这些答案。

现在的一种方法是使用事件参数上的key属性，该参数随DOM keyup和keypress事件而来。下面是一个简单的例子:

document.onkeypress = (event) => {
    if (event.key === 'Meta') {
        console.log("Mac or Windows key was pressed!");
    } else {
        console.log("Another key was pressed")
    }
}

这将在Mac上的cmd键下触发(参见MDN文档上的Meta)。这里唯一需要注意的是，对于支持它的用户键盘/操作系统，它也会在Windows按键上触发。

如果你需要更细粒度地了解哪个元键被按下了，你可以使用事件上的代码属性，它可以是MetaLeft或MetaRight，这取决于按下的物理元键(cmd)。

var element = //the DOM element to listen for the key on.
element.onkeyup = function(e) {
   if(e.metaKey) {
      //command key was pressed
   }
}

下面是我在AngularJS中如何做到的

app = angular.module('MM_Graph')

class Keyboard
  constructor: ($injector)->
    @.$injector  = $injector
    @.$window    = @.$injector.get('$window')                             # get reference to $window and $rootScope objects
    @.$rootScope = @.$injector.get('$rootScope')

  on_Key_Down:($event)=>
    @.$rootScope.$broadcast 'keydown', $event                             # broadcast a global keydown event

    if $event.code is 'KeyS' and ($event.ctrlKey or $event.metaKey)       # detect S key pressed and either OSX Command or Window's Control keys pressed
      @.$rootScope.$broadcast '', $event                                  # broadcast keyup_CtrS event
      #$event.preventDefault()                                             # this should be used by the event listeners to prevent default browser behaviour

  setup_Hooks: ()=>
    angular.element(@.$window).bind "keydown", @.on_Key_Down              # hook keydown event in window (only called once per app load)
    @

app.service 'keyboard', ($injector)=>
  return new Keyboard($injector).setup_Hooks()