el.el

(defun ruby-tag (tagname)
  (or (equal tagname "%")
      (equal tagname "%=")
      (equal tagname "%#")))

(defun property-tag (tagname)
  (or (equal tagname "a")
      (equal tagname "div")
      (equal tagname "img")
      (equal tagname "span")))

(defun insert-tag (tagname)
  "Insert tag around point"
  (interactive "sTag name: ")
  (cond ((equal tagname "end")
         (insert "<% end %>"))

        ((equal tagname "else")
         (insert "<% else %>"))

        ((equal tagname "!")
         (insert "<!--  -->")
         (goto-char (- (point) 4)))

        ((equal tagname "#")
         (insert "<%#  %>")
         (goto-char (- (point) 3)))

        (t
         (progn
           (insert "<" tagname
                   (cond
                    ((equal tagname "a") " href=\"\"")
                    ((or (equal tagname "div") (equal tagname "span")) " class=\"\"")
                    ((equal tagname "img") " src=\"\"")
                    ((equal tagname "script") " type=\"text/javascript\"")
                    ((ruby-tag tagname) " %")
                    (t ""))
                   ">")

           (if (ruby-tag tagname)
               (goto-char (- (point) 3))

             (let ((final-location (point)))
               (insert "</" tagname ">")
               (if (property-tag tagname)
                   (goto-char (- final-location 2))
                 (goto-char final-location))))))))