DOMNamedNodeMap::count (PHP 7 >= 7.2.0, PHP 8)DOMNamedNodeMap::count — Get number of nodes in the map 说明 public DOMNamedNodeMap::count(): int Gets the number of nodes in the map. 参数 此函数没有参数。 返回值 Returns the number of nodes in the map, which is identical to the length property.