htmlegalize evolved

(defun roadie-htmlegalize-region (b e)
  "Replace \"&\", \"<\", and \">\" with their HTML escape codes, from B to E.
Is there anything else that should be done to escape HTML?"
  (interactive "r")
  (save-excursion
    (let ((em (copy-marker e)))
      (goto-char b)
      (while (search-forward " & " em t)
        (replace-match " &amp; " nil t))
      (goto-char b)
      (while (search-forward " < " em t)
        (replace-match " &lt; " nil t))
      (goto-char b)
      (while (search-forward " > " em t)
        (replace-match " &gt; " nil t))
      (goto-char b)
      (while (search-forward "ä" em t)
        (replace-match "&auml;" nil t))
      (goto-char b)
      (while (search-forward "ö" em t)
        (replace-match "&ouml;" nil t))
      (goto-char b)
      (while (search-forward "ü" em t)
        (replace-match "&uuml;" nil t))
      (goto-char b)
      (while (search-forward "Ä" em t)
        (replace-match "&Auml;" nil t))
      (goto-char b)
      (while (search-forward "Ö" em t)
        (replace-match "&Ouml;" nil t))
      (goto-char b)
      (while (search-forward "Ü" em t)
        (replace-match "&Uuml;" nil t))
      (goto-char b)
      (while (search-forward "ß" em t)
        (replace-match "&szlig;" nil t))
      )))