NamedNodeMap: setNamedItem() method

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

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

<span one="one" two="two"></span>
<pre test="testValue"></pre>

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;

Specification

Specification
DOM Standard # dom-namednodemap-setnameditem

Browser compatibility

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