Dispatch a keyboard

keyboard-event-trigger.js

/*
  Chrome does not let you modify the keyCode prop when you trigger it, so it defaults to 0. 
  You can use this code to trigger a keydown with a char code of 0 in chrome. 

  If you use initKeyEvent instead of initKeyboardEvent, it will work in FF 
  (the bellow example would trigger keydown with a char code of 65 in FF).
*/

document.addEventListener( 'keydown', function( event ){
  console.log( event.keyCode )
}, false);

var event = document.createEvent( 'KeyboardEvent' );
event.initKeyboardEvent( 'keydown', true, false, null, 0, false, 0, false, 65, 0 );
document.dispatchEvent( event );