<!doctype html>
<body style="position: relative">
  <div id="container" style="position: relative; height: 300px">
    <div style="position:absolute; top: 0; left: 0">
      <textarea rows="6">
        You should be seeing the "Should see me" text.
        a
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        i
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        l
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        n
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        t
        u
        Should see me.
      </textarea>
    </div>
  </div>
  <script>
    var textarea = document.querySelector("textarea");
    textarea.scrollTop = textarea.scrollHeight
    document.getElementById("container").style.overflow = "hidden";
  </script>
</body>