NamedNodeMap: setNamedItem() method

{{APIRef("DOM")}} 

The setNamedItem() method of the {{domxref("NamedNodeMap")}}  interface puts the {{domxref("Attr")}}  identified by its name in the map. If there is already an {{domxref("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 {{domxref("DOMException")}} 
  • : Thrown if the attribute is still part of another map.

Example

<span class="foo" id="bar"></span>
<pre contenteditable></pre>

const span = document.querySelector("span");
const pre = document.querySelector("pre");

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

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

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

pre.textContent = result;

{{EmbedLiveSample("Example", "100%", 160)}} 

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}}