Which keycode for escape key with jQuery

Try with the keyup event:

$(document).on('keyup', function(e) {
  if (e.key == "Enter") $('.save').click();
  if (e.key == "Escape") $('.cancel').click();
});

Rather than hardcode the keycode values in your function, consider using named constants to better convey your meaning:

var KEYCODE_ENTER = 13;
var KEYCODE_ESC = 27;

$(document).keyup(function(e) {
  if (e.keyCode == KEYCODE_ENTER) $('.save').click();
  if (e.keyCode == KEYCODE_ESC) $('.cancel').click();
});

Some browsers (like FireFox, unsure of others) define a global KeyEvent object that exposes these types of constants for you. This SO question shows a nice way of defining that object in other browsers as well.

27 is the code for the escape key. :)

Your best bet is

$(document).keyup(function(e) { 
    if (e.which === 13) $('.save').click();   // enter 
    if (e.which === 27) $('.cancel').click(); // esc   

    /* OPTIONAL: Only if you want other elements to ignore event */
    e.preventDefault();
    e.stopPropagation();
});

Summary

• which is more preferable than keyCode because it is normalized
• keyup is more preferable than keydown because keydown may occur multiple times if user keeps it pressed.
• Do not use keypress unless you want to capture actual characters.

Interestingly Bootstrap uses keydown and keyCode in its dropdown component (as of 3.0.2)! I think it's probably poor choice there.

Related snippet from JQuery doc

While browsers use differing properties to store this information, jQuery normalizes the .which property so you can reliably use it to retrieve the key code. This code corresponds to a key on the keyboard, including codes for special keys such as arrows. For catching actual text entry, .keypress() may be a better choice.

Other item of interest: JavaScript Keypress Library

I'm was trying to do the same thing and it was bugging the crap out of me. In firefox, it appears that if you try to do some things when the escape key is pressed, it continues processing the escape key which then cancels whatever you were trying to do. Alert works fine. But in my case, I wanted to go back in the history which did not work. Finally figured out that I had to force the propagation of the event to stop as shown below...

if (keyCode == 27)
{
    history.back();

    if (window.event)
    {
        // IE works fine anyways so this isn't really needed
        e.cancelBubble = true;
        e.returnValue = false;
    }
    else if (e.stopPropagation)
    {
        // In firefox, this is what keeps the escape key from canceling the history.back()
        e.stopPropagation();
        e.preventDefault();
    }

    return (false);
}

To get the hex code for all the characters: http://asciitable.com/

$(document).on('keydown', function(event) {
   if (event.key == "Escape") {
       alert('Esc key pressed.');
   }
});