anchor.diff:  
   (memoize
    (defun valid-attribute? (tag name)
  -   (or (begins (string-downcase name) "data-")
  +   (or (begins name "data-")
  +       (begins name "DATA-")
          (eql name :attrs)
          (global-attribute? name)
  +       (aria-attribute? name)
          (let ((permitted (assoc tag *permitted-attributes*
                                  :test #'string=)))
            (or (find name permitted :test #'string=)
  
positive.code: (defparameter *core-attributes*
    '(accesskey class contenteditable contextmenu dir draggable
      dropzone hidden id lang spellcheck style tabindex title))
  
  (defparameter *event-handler-attributes*
    '(onabort onblur oncanplay oncanplaythrough onchange onclick
  
negative.code: 
  (defun global-attribute? (name)
    (find name *global-attributes* :test #'string=))
  
  (defun aria-attribute? (name)
    (find name *aria-attributes* :test #'string=))
  