event.keyCode is different in keydown/keyup and keypress

Question

I'm creating a text box for a user defined shortcut key combination, where it just prints out the modifiers and key.

I don't really care whether its set as you press or release the keys, so I started with the keypress event. Firstly, modifiers seemed to affect the keycode (such as shift giving caps which implies keycode is not a key code at all but a typed character code) but also preventDefault doesn't seem to work properly so I changed to keydown. This introduced a discrepancy in event.keyCode. For example, comma , produced a delightful ascii keyCode=44 but now it's a disgusting keyCode=188.

A test page: http://www.javascripter.net/faq/keyboardeventproperties.htm

I'd really like to have some standardized key codes here or at the very least some consistent ones. My request is for a workaround. Either:

What's the best way to get the printable character (ignoring modifiers, so ,/< are considered the same key and give ,) for the weird but more consistent keydown/keyup?
Can keypress be made more like keydown/keyup to actually give the key that was pressed and is there a mechanism like preventDefault to stop the browser intercepting shortcuts?

Related: http://www.javascripter.net/faq/keycodes.htm

It's not clear what you want. Do you want a different code for `a` and `A`? — Barmar, Jul 03 '14 at 10:09
Is this question helpful: http://stackoverflow.com/questions/3396754/onkeypress-vs-onkeyup-and-onkeydown — Barmar, Jul 03 '14 at 10:10
@Barmar keypress has issues, as already explained. No, I'm after a shortcut. `a` and `A` are the same physical key and I want the key code to reflect that (updated Q). — jozxyqk, Jul 03 '14 at 10:17

score 1 · Answer 1 · answered Jul 03 '14 at 10:19

For the moment, I'm just going to use keydown and a modified version of this: http://www.javascripter.net/faq/fromkeycode.js

function fromKeyCode(n) {
    if( 47<=n && n<=90 ) return unescape('%'+(n).toString(16))
    if( 96<=n && n<=105) return (n-96).toString()
    if(112<=n && n<=135) return 'F'+(n-111)
    if(n==8)  return 'Backspace'
    if(n==9)  return 'Tab'
    if(n==13) return 'Enter'
    if(n==16) return 'Shift'
    if(n==17) return 'Ctrl'
    if(n==18) return 'Alt'
    if(n==19) return 'Pause'
    if(n==20) return 'Caps_lock'
    if(n==27) return 'Esc'
    if(n==32) return 'Space'
    if(n==33) return 'Page_up'
    if(n==34) return 'Page_down'
    if(n==35) return 'End'
    if(n==36) return 'Home'
    if(n==37) return 'Left'
    if(n==38) return 'Up'
    if(n==39) return 'Right'
    if(n==40) return 'Down'
    if(n==42) return '*' //Opera
    if(n==43) return '+' //Opera
    if(n==45) return 'Insert'
    if(n==46) return 'Delete'
    if(n==91) return 'Meta'
    if(n==92) return 'Meta'
    if(n==106) return '*'
    if(n==107) return '+'
    if(n==109) return '-'
    if(n==110) return '.'
    if(n==111) return '/'
    if(n==144) return 'Num_lock'
    if(n==145) return 'Scroll_lock'
    if(n==186) return ';'
    if(n==187) return '='
    if(n==188) return ','
    if(n==189) return '-'
    if(n==190) return '.'
    if(n==191) return '/'
    if(n==192) return '\`'
    if(n==219) return '['
    if(n==220) return '\\'
    if(n==221) return ']'
    if(n==222) return '\''
    if(n==224) return 'Meta'
    return ""
}

event.keyCode is different in keydown/keyup and keypress

1 Answers1