/// <summary>
 /// Add or remove one or more classes to the element, depending on either the class's presence.
 /// </summary>
 public static HElement ToggleClass(this HElement element, String[] className)
 {
     if (element != null && className != null)
     {
         foreach (var cName in className)
         {
             if (element.HasClass(cName))
             {
                 element.RemoveClass(cName);
             }
             else
             {
                 element.AddClass(cName);
             }
         }
     }
     return(element);
 }