NamedNodeMap: setNamedItemNS() method

{{APIRef("DOM")}} 

The setNamedItemNS() method of the {{domxref("NamedNodeMap")}}  interface puts the {{domxref("Attr")}}  identified by its name in the map. If there was already an {{domxref("Attr")}}  with the same name in the map, it is replaced.

[!NOTE] This method is an alias of setNamedItem() you can use them interchangeably.

Syntax

setNamedItemNS(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 {{domxref("DOMException")}} 
  • : Thrown if the attribute is still part of another map.

Example

<span ob:one="one"></span>
<pre></pre>

const parser = new DOMParser();
// ob:one in <span> is not in a namespace, while ob:one in <warning>, is.
const xmlString =
  '<warning ob:one="test" xmlns:ob="http://www.example.com/ob">Beware!</warning>';
const doc = parser.parseFromString(xmlString, "application/xml");

const span = document.querySelector("span");
const pre = document.querySelector("pre");
const warning = doc.querySelector("warning");
const attrMap = span.attributes;

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

result += "We remove `one` from '<span>' and adds it to '<pre>'.\n";
const one = warning.attributes.removeNamedItemNS(
  "http://www.example.com/ob",
  "one",
);
attrMap.setNamedItemNS(one);
result += `The '<span>' element now contains ${span.attributes.length} attributes:\n\n`;
result += "Prefix\tLocal name\tQualified name\n";
result += "=========================================\n";

for (const attr of attrMap) {
  result += `${attr.prefix}\t${attr.localName}\t\t${attr.name}\n`;
}

pre.textContent = result;

{{EmbedLiveSample("Example", "100%", 200)}} 

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}}