Accented characters doesn't work on menu keydown

jsfiddle.net: https://jsfiddle.net/yeuL9b1o/

Using french keyboard or other non-english/non-german keyboards will converted to wrong characters from String.fromCharCode( event.keyCode );

I can't use i.e.: the é to select the correct entry via keyboard.

Maybe using event.key instead of String.fromCharCode(event.keyCode) will works?

event.keyCode is deprecated according to MDN.