/Web APIs

Element: computedStyleMap() method

The computedStyleMap() method of the Element interface returns a StylePropertyMapReadOnly interface which provides a read-only representation of a CSS declaration block that is an alternative to CSSStyleDeclaration.





Return value


We start with some simple HTML: a paragraph with a link, and a definition list to which we will add all the CSS Property / Value pairs.

  <a href="https://example.com">Link</a>
<dl id="regurgitation"></dl>

We add a little bit of CSS

a {
  --color: red;
  color: var(--color);

We add JavaScript to grab our link and return back a definition list of all the CSS property values using computedStyleMap().

// get the element
const myElement = document.querySelector("a");

// get the <dl> we'll be populating
const stylesList = document.querySelector("#regurgitation");

// Retrieve all computed styles with computedStyleMap()
const allComputedStyles = myElement.computedStyleMap();

// iterate thru the map of all the properties and values, adding a <dt> and <dd> for each
for (const [prop, val] of allComputedStyles) {
  // properties
  const cssProperty = document.createElement("dt");

  // values
  const cssValue = document.createElement("dd");

In browsers that support computedStyleMap(), you'll see a list of all the CSS properties and values. In other browsers you'll just see a link.

Did you realize how many default CSS properties a link had? Update the 'a' to the 'p', and you'll notice a difference in the margin-top and margin-bottom default computed values.


Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
computedStyleMap 66 79 No No 53 16.4 66 66 No 47 16.4 9.0

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