code: function toggleElementClass( elm, className, on ) {
  		var oldClassName = elm.className;
  		var newClassName = toggleClass(oldClassName, className, on);
  		if (newClassName != oldClassName) {
  			elm.className = newClassName;
  			elm.parentNode.className += EMPTY_STRING;
  		}
  	}
docs: --[ toggleElementClass() ]------------------------------------------- toggles a single className on an element