NamedNodeMap: setNamedItem() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

The setNamedItem() method of the NamedNodeMap interface puts the Attr identified by its name in the map. If there is already an Attr with the same name in the map, it is replaced.

Syntax

js
setNamedItem(attr)

Parameters

attr

the attribute to insert in the map.

Return value

Returns the old attribute if replaced, or null if the attribute is new.

Exceptions

InUseAttributeError DOMException

Thrown if the attribute is still part of another map.

Example

html
<span one="one" two="two"></span>
<pre test="testValue"></pre>
js
const span = document.querySelector("span");
const pre = document.querySelector("pre");
const attrMap = pre.attributes;

let result = `The '<pre>' element initially contains ${attrMap.length} attributes.\n\n`;

result += "We remove `one` from `<span>` and adds it to `<pre>`.\n";
const one = span.attributes.removeNamedItem("one");
attrMap.setNamedItem(one);
result += `The '<pre>' element now contains ${pre.attributes.length} attributes.\n\n`;

result += "We get 'two' from '<span>' and try to adds it to '<pre>'.\n";
const two = span.attributes.getNamedItem("two");
try {
  attrMap.setNamedItem(two);
} catch (error) {
  result += `An exception has been raised: ${error.name}.\n`;
}

pre.textContent = result;

Specifications

Specification
DOM Standard
# dom-namednodemap-setnameditem

Browser compatibility

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