Just think: were HTML replaced with SXML, JavaScript with Common Lisp & CSS with something like LASS, we might have pages which look like this:

    (html
     (head
      (style (let ((bg #x0088ee)
                   (fg #x00ee88))
               (body (background bg)
                     (foreground fg))
               (body.inverted (foreground fg)
                              (background bg))))
      (script (defun invert ()
                (with-slots (class-list)
                    (get-element-by-tag document 'body)
                  (setf class-list
                        (if (find 'inverted class-list)
                            (remove 'inverted class-list)
                          (cons 'inverted class-list)))))))
     (body
      (button (@ (on-click (invert))) "Click me")
      (p "This is some text.")))

I contend that this is a massive improvement.