This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The illuminance property of the AmbientLightSensor interface returns the current light level in lux of the ambient light level around the hosting device.

If a feature policy blocks use of a feature it is because your code is inconsistent with the policies set on your server. This is not something that would ever be shown to a user. See Feature-Policy for implementation instructions.


var level = AmbientLightSensor.illuminance


A Number indicating the current light level in lux.


if ( 'AmbientLightSensor' in window ) {
  const sensor = new AmbientLightSensor();
  sensor.onreading = () => {
    console.log('Current light level:', sensor.illuminance);
  sensor.onerror = (event) => {
    console.log(, event.error.message);


Specification Status Comment
Generic Sensor API Candidate Recommendation Defines sensors in general.
Ambient Light Sensor
The definition of 'illuminance' in that specification.
Candidate Recommendation

Browser compatibility

BCD tables only load in the browser