How to capture mac's command key via javascript?

Question

So, that's the question =)

How to capture mac's command key via javascript?

Answer 1

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

Answer 2

Unlike Shift/Alt/Ctrl, Mac/Apple key is not considered as a modifier key--instead, you should hook on keydown/keyup and record when a key is pressed and then depressed based on event.keyCode.

Unfortunately, these key codes are browser-dependent:

Firefox: 224
Opera: 17
WebKit (Safari/Chrome): 91 (Left Apple) or 93 (Right Apple)

You might be interested in reading this article: JavaScript Madness: Keyboard Events from which I mastered that knowledge.