Web/API/HTMLImageElement/decoding

The decoding property of the HTMLImageElement interface represents a hint given to the browser on how it should decode the image.

Syntax

refStr = imgElem.decoding;
imgElem.decoding = refStr;

Values

A DOMString representing the decoding hint. Possible values are:

• sync: Decode the image synchronously for atomic presentation with other content.
• async: Decode the image asynchronously to reduce delay in presenting other content.
• auto: Default mode, which indicates no preference for the decoding mode. The browser decides what is best for the user.

Usage notes

The decoding property allows you to control whether or not the browser is allowed to try to parallelize loading your image. If doing so would cause problems, you can specify sync to disable asynchronous loading. This can be useful when applied to <img> elements, but may be even more so when used for offscreen image objects.

Examples

var img = new Image();
img.decoding = 'sync';
img.src = 'img/logo.png'; 

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'decoding' in that specification.	Living Standard

Browser compatibility

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
decoding	Chrome Full support 65	Edge Full support ≤79	Firefox Full support 63	IE No support No	Opera Full support Yes	Safari Full support 11.1	WebView Android Full support 65	Chrome Android Full support 65	Firefox Android Full support 63	Opera Android ?	Safari iOS Full support 11.3	Samsung Internet Android Full support 9.0

Legend

Full support  

Full support

No support  

No support

Compatibility unknown  

Compatibility unknown

HTMLImageElement.decoding by Mozilla Contributors is licensed under CC-BY-SA 2.5.