editor/reftests/caret_on_textarea_lastline.html

<!DOCTYPE html>
<html>
<body onload="loaded()">
<script>
  function loaded() {
    var t = document.querySelector('textarea');
    t.selectionStart = t.selectionEnd = t.value.length;
    t.focus();
  }
</script>
<textarea>foo
</textarea>
</body>
</html>