Question: i was wondering how do i trigger the event keyCode composed by `Ctrl+z` and the event keycode composed by `Ctrl+Shift+z` ?

Answer: 
Use `e.which` which has been normalized cross browser by jquery. 

```
$(document).keydown(function(e){
      if( e.which === 90 && e.ctrlKey && e.shiftKey ){
         console.log('control + shift + z'); 
      }
      else if( e.which === 90 && e.ctrlKey ){
         console.log('control + z'); 
      }          
}); 

```
Ctrl and Shift keys are included in key events but keycode is refereeing to which key you press. Ctrl and Shift are control keys and they have their own keys in key events. 

For example if you press `Ctrl+Shift+Z` then keydown event would be this:

```
{
    altGraphKey: false
    altKey: false
    bubbles: true
    cancelBubble: false
    cancelable: true
    charCode: 0
    clipboardData: undefined
    ctrlKey: true
    currentTarget: null
    defaultPrevented: true
    detail: 0
    eventPhase: 0
    keyCode: 90
    keyIdentifier: "U+004C"
    keyLocation: 0
    layerX: 0
    layerY: 0
    metaKey: false
    pageX: 0
    pageY: 0
    returnValue: false
    shiftKey: true
    srcElement: HTMLTextAreaElement
    target: HTMLTextAreaElement
    timeStamp: 1318460678544
    type: "keydown"
    view: DOMWindow
    which: 90
    __proto__: KeyboardEvent
}

```

As you can see there is two key for `Ctrl` and `Shift` keys that are true because those keys were pressed while pressing `Z`.

So you can detect this event like this:

```
document.addEventListener('keydown', function(event){
  if(event.keyCode == 90 && event.ctrlKey && event.shiftKey){
   // do your stuff
  }
}, false);

```

Note: You should listen to `keydown` for multiple key keyboard shortcuts. `keyup` wouldn't work.