NamedNodeMap

DOM dom

Baseline: Widely available on the web, in every major browser since Jul 2015, and long enough to count on (since Jan 2018).

niso: No WPT tests. WPT maps no test to it. WPT results recorded at f3b4fa8, 2026-11-10; web-features 3.45.0. WPT tests · niso's support · Attr, CDATASection, CharacterData, Comment

NamedNodeMap is an interface in idl/dom.webidl, exposed in Window. What it does is on MDN; this page says what niso has of it.

The standard’s named properties are not supported yet.

Status

The web features its members belong to, each with its Baseline status on the web and how much of the feature’s WPT suite passes in niso (see Web platform support).

Feature	On the web	In niso	Members
DOM	Widely available	No WPT tests WPT maps no test to it	9

Members

length

attribute

readonly attribute unsigned long length;

int32_t niso_named_node_map_get_length(niso_dom* dom, niso_handle self, uint32_t* out);

item()

operation

getter Attr? item(unsigned long index);

int32_t niso_named_node_map_item(niso_dom* dom, niso_handle self, uint32_t index, niso_handle* out);

getNamedItem()

operation

Attr? getNamedItem(DOMString qualifiedName);

int32_t niso_named_node_map_get_named_item(niso_dom* dom, niso_handle self, const char* qualified_name, size_t qualified_name_len, niso_handle* out);

getNamedItemNS()

operation

Attr? getNamedItemNS(DOMString? namespace, DOMString localName);

int32_t niso_named_node_map_get_named_item_ns(niso_dom* dom, niso_handle self, const char* namespace_, size_t namespace__len, const char* local_name, size_t local_name_len, niso_handle* out);

setNamedItem()

operation

Attr? setNamedItem(Attr attr);

int32_t niso_named_node_map_set_named_item(niso_dom* dom, niso_handle self, niso_handle attr, niso_handle* out);

setNamedItemNS()

operation

Attr? setNamedItemNS(Attr attr);

int32_t niso_named_node_map_set_named_item_ns(niso_dom* dom, niso_handle self, niso_handle attr, niso_handle* out);

removeNamedItem()

operation

Attr removeNamedItem(DOMString qualifiedName);

int32_t niso_named_node_map_remove_named_item(niso_dom* dom, niso_handle self, const char* qualified_name, size_t qualified_name_len, niso_handle* out);

removeNamedItemNS()

operation

Attr removeNamedItemNS(DOMString? namespace, DOMString localName);

int32_t niso_named_node_map_remove_named_item_ns(niso_dom* dom, niso_handle self, const char* namespace_, size_t namespace__len, const char* local_name, size_t local_name_len, niso_handle* out);