index.html

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Base64</title>
    <script type="text/javascript">
      function waitForElement(id, callback) {
        var poops = setInterval(function () {
          if (document.getElementById(id)) {
            clearInterval(poops);
            callback();
          }
        }, 100);
      }

      waitForElement('e', function () {
        console.log('asseatingsex');
        let params = new URLSearchParams(location.search);
        let yes = params.get('t');
        console.log(atob(yes));
        document.getElementById('e').innerHTML = atob(yes);
      });
    </script>
  </head>
  <body>
    <p id="e"></p>
  </body>
</html>