@keyframes click { 0% { background-color: red; transform: translate(0, 0); } 100% { background-color: purple; transform: translate(0px, 20px); } }

let clicked = false;

button.addEventListener('click', function() {
  clicked = !clicked;
  if (clicked) {
    button.style.animation = 'click 5s';
  } else {
    button.style.animation = '';
  }
});