Change background after notification

Question

Why on this page:

https://jsfiddle.net/eddnhc5f/

When I press a key con the border of Firefox and Microsoft, the background changes before the warning, but in Opera and Chrome after clicking on the confirmation button.

function getKeyup(key) {
  if (key == null) {
    keycode = event.keyCode;
    // To Mozilla
  } else {
    keycode = key.keyCode;
  }
}

function TEST() {
  document.body.style.backgroundColor = "BLACK";
  alert('Hello');
  return false;
}

function getKey(key) {
  if (key == null) {
    keycode = event.keyCode;
    // To Mozilla
  } else {
    keycode = key.keyCode;
  }
  if (keycode == 67) {
    //alert(condcheck);

    TEST();
    return false;
  }
}
$(document).ready(function() {
  $(document).keydown(function(eventObj) {
    getKey(eventObj);
  });
  $(document).keyup(function(eventObj) {
    getKeyup(eventObj);
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
TEST

Run codeHide result

Answer 1

check out this demo

I changed the TEST () function.

function getKeyup(key){
    if ( key == null ) {
        keycode = event.keyCode;
    // To Mozilla
    } else {
        keycode = key.keyCode;
    }
}
function TEST()
{
//document.body.style.backgroundColor = "BLACK";
alert('Hello');
document.body.style.backgroundColor = "BLACK";
return false;
}
function getKey(key){
    if ( key == null ) {
        keycode = event.keyCode;
    // To Mozilla
    } else {
        keycode = key.keyCode;
    }
    if (keycode == 67){
        //alert(condcheck);

        TEST();
        return false;
    } 
}
$(document).ready( function (){
    $(document).keydown(function (eventObj){
        getKey(eventObj);
    });
    $(document).keyup(function (eventObj){
        getKeyup(eventObj);
    });    
});