NamedNodeMap

NamedNodeMap is an interface in the Document Object Model (DOM) that represents a collection of nodes that can be accessed by name. It is most commonly used to model the attributes of a DOM element, where each attribute is represented by an Attr node within the map.

It is not a generic map or array; it is a live collection. The items in the map are Attr nodes, with each node’s name corresponding to an attribute’s name. The collection provides access by name as well as by index, and it exposes a length property.

Standard methods include getNamedItem(name), setNamedItem(node), removeNamedItem(name), and item(index). In addition, newer specifications introduce namespace-aware variants getNamedItemNS, setNamedItemNS, and removeNamedItemNS to handle attributes within a specific XML namespace.

Usage typically involves an element’s attributes property, which returns a NamedNodeMap. You can retrieve an attribute node by name, for example map.getNamedItem('id'), and then read its value via node.value. While you can manipulate attributes through these low‑level nodes, most code prefers the higher-level Element.getAttribute and Element.setAttribute APIs. The map is live, meaning changes to the element’s attributes are reflected immediately in the NamedNodeMap.

See also: Element, Attr, NodeList, and the broader Document Object Model (DOM) specification.