docs: function (el, attrName) {
  			attrName = attrName.toLowerCase();
  			var oldValue;
  			if (!getMutationObserver()) {
  				oldValue = attr.get(el, attrName);
  			}
  
  			var special = attr.special[attrName];
  			var setter = special && special.set;
  			var remover = special && special.remove;
  			var test = getSpecialTest(special);
  
  			if(typeof remover === "function" && test.call(el)) {
  				remover.call(el);
  			} else if(typeof setter === "function" && test.call(el)) {
  				setter.call(el, undefined);
  			} else {
  				el.removeAttribute(attrName);
  			}
  
  			if (!getMutationObserver() && oldValue != null) {
  				attr.trigger(el, attrName, oldValue);
  			}
  		}