<!DOCTYPE html>
<html>
  <body>
    <script>
      document.addEventListener("DOMContentLoaded", function() {
        var t = document.querySelector("textarea");
        t.focus();
        document.querySelector("#dst").appendChild(t);
      }, false);
    </script>
    <div>
      <textarea>I
        am
        a
        long
        long
        long
        long
        textarea
      </textarea>
    </div>
    <div id="dst"></div>
  </body>
</html>