https://www.humanbenchmark.com/

reactiontime.js

(function() {
  // https://stackoverflow.com/a/52549234
  function simulateMouseClick(targetNode) {
    function triggerMouseEvent(targetNode, eventType) {
      var clickEvent = document.createEvent('MouseEvents');
      clickEvent.initEvent(eventType, true, true);
      targetNode.dispatchEvent(clickEvent);
    }
    ["mouseover", "mousedown", "mouseup", "click"].forEach(function(eventType) {
      triggerMouseEvent(targetNode, eventType);
    });
  }

  // https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver
  const config = {
    attributes: true,
    childList: true,
    subtree: true
  };
  const callback = function(mutationsList, observer) {
    for (let mutation of mutationsList) {
      if (mutation.type === 'attributes') {
        if ((mutation.target.classList.contains('view-go') || mutation.target.classList.contains('view-result'))) {
          simulateMouseClick(targetNode);
        } else {
          targetNode.querySelector('h1 div').textContent = 'Wait for [ ᴼ ▃ ᴼ ]_/¯';
        }
      }
      if (targetNode.querySelector('.hero-button') !== null) {
        observer.disconnect();
      }
    }
  };
  const observer = new MutationObserver(callback);

  // [ ᴼ ▃ ᴼ ]_/¯
  const targetNode = document.querySelector('.reaction-time-test');
  if (targetNode === null) return;
  observer.observe(targetNode, config);
  simulateMouseClick(targetNode);
})();