How to capture ALT+N on keypress in JavaScript

Try :

window.addEventListener('keydown', function(e) {
  if (e.altKey == true && e.keyCode == 78)
    console.log('Alt + N'); 
});

Using keypress event doesn't work for me for Alt+N and for any combination with Alt for that matter. Some combinations are working with Ctrl and some aren't.

However, when I listen for keydown and keyup events, I am able to log these events. So, I guess you could listen for keydown event on Alt and if there is a keydown event for N before Alt generates keyup, you have successfully detected a Alt+N combo.

I am not sure about why this happens though.

EDIT

According to Mozilla documentation,

The keypress event is fired when a key that produces a character value is pressed down. Examples of keys that produce a character value are alphabetic, numeric, and punctuation keys.

Examples of keys that don't produce a character value are modifier keys such as Alt, Shift, Ctrl, or Meta.

As for why some shortcuts work in Chrome, while some do not, Mozilla says

Chrome does not fire the keypress event for known keyboard shortcuts. Which keyboard shortcuts are known depends on the user's system. Use the keydown event to implement keyboard shortcuts.