NamedNodeMap.length

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.

lengthNamedNodeMap インターフェイスの読み取り専用プロパティで、このマップに格納されているオブジェクトの数を示します。

このマップにあるオブジェクトの数を示す数値です。

html
<pre zero="test" one="test" two="test"></pre>
js
const pre = document.getElementsByTagName("pre")[0];
const attrMap = pre.attributes;

let result = `The 'test' attribute contains ${attrMap.length} attributes.\n`;

pre.textContent = result;

仕様書

Specification
DOM
# dom-namednodemap-length

ブラウザーの互換性

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
length

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support