HTMLSourceElement: sizes property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2017.

The sizes property of the HTMLSourceElement interface is a string representing a list of one or more sizes, representing sizes between breakpoints, to which the resource applies.

It reflects the sizes attribute of the <source> element.

Value

A string.

Examples

html
<picture>
  <source
    id="el"
    srcset="medium-pic.jpg"
    type="image/jpeg"
    sizes="(50em <= width <= 60px) 50em,
           (30em <= width < 50em) 30em" />
</picture>

js
const el = document.getElementById("el");
console.log(el.sizes); // Output: "(50em <= width <= 60px) 50em, (30em <= width < 50em) 30em"
el.sizes = "(50em <= width <= 60px) 100em, (30em <= width < 50em) 60em"; // Updates the sizes value