This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Indicates how bright the screen's backlight is, on a scale from 0 (very dim) to 1 (full brightness); this value is a double-precision float.

You can read and write this attribute even when the screen is disabled, but the backlight is off while the screen is disabled. If you write a value of X into this attribute, the attribute may not have the same value X when you later read it. Most screens don't support as many different brightness levels as there are doubles between 0 and 1. The value's precision might be reduced before storing it.


screenBrightness = window.screen.mozBrightness;

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support ? 12.0 (12.0)[1] ? ? ?
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support ? ? 12.0 (12.0)[1] ? ? ?

[1] In order to use screen.mozBrightness you have to set the preference dom.screenBrightnessProperty.enabled to true in about:config.


Not part of specification.


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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API Property