Note this will appear to do nothing because the code is long running

When you click the button the event handler below will run

      const btn = document.querySelector('button');
      btn.addEventListener('click', () => {
        let myDate;
        for(let i = 0; i < 10000000; i++) {
          let date = new Date();
          myDate = date
        }

        console.log(myDate);

        let pElem = document.createElement('p');
        pElem.textContent = 'This is a newly-added paragraph.';
        document.body.appendChild(pElem);
      });