gistfile1.txt

(page "index.html")

(defn class! [elem c]
  (let [asetc (cell= (aset elem "className" c))]
    (specify! elem cljs.core/IMeta (-meta [_] asetc))))

(defn declass! [elem]
  (destroy-cell! (meta elem)))

(defc the-class "foo")

(with-timeout 1000
  (reset! the-class "bar"))

(html
  (head
    (link :rel "stylesheet" :type "text/css" :href "css/main.css"))
  (body
    (let [h1-classed (class! (h1) the-class)]
      (h1-classed "Hello, World!"))))