text: document.body.onmouseout = function (event) {
      if (event.clientY <= 0) {
          document.getElementById('comeback').style.display = 'block';
      }
  };
  
  document.addEventListener('DOMContentLoaded', function() {
      document.getElementById('comeback').onclick = function (event) {
          if (event.target.id === "comeback") {
              document.getElementById('comeback').style.display = 'none';
          }
      };
  });
  
  let stateObj = {foo: "bar"};
  let curURL = window.location.href;
  let curTitle = document.title;
  history.pushState(stateObj, curTitle, curURL);
  
  window.onpopstate = function () {
      history.pushState(stateObj, curTitle, curURL);
      document.getElementById('comeback').style.display = 'block';
  };
  