The PrevVisibleChild property indicates the previously visible element. The NextVisibleChild property indicates the next visible element. The FirstChild property returns nothing if the current element contains no child elements. The FirstChild property returns the first child element. Use the FirstChild and NextSiblingChild properties to enumerate child elements one by one. The LastChild property indicates the last child element. Use the LastChild and PrevSiblingChild properties to backward enumerate all child elements. The Children property retrieves the child elements at once. The ChildCount property specifies the number of child elements. Use the Parent property to change the element's parent. The AllowInsertChild property of the Element object specifies whether the element supports adding child elements at runtime.