WakeLock: request() method
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The request()
method of the WakeLock
interface returns a Promise
that fullfills with a WakeLockSentinel
object if the system screen wake lock is granted.
The screen wake lock prevents device screens from dimming or locking when an application needs to keep running.
Syntax
request(type)
Parameters
type
Optional-
A string specifying the screen wake lock type, from among the following enumerated types:
screen
-
Prevents the screen from turning off. Only visible documents can acquire the screen wake lock.
If no type
parameter is explicitly specified, the request()
method defaults to using the screen
type.
Return value
A Promise
that resolves with a WakeLockSentinel
object.
Exceptions
NotAllowedError
DOMException
-
Thrown when wake lock is not available, which can happen because:
- Use of this feature is blocked by a Permissions Policy.
- The document is not fully active.
- The document's visibility state is
hidden
. - The User Agent could not acquire platform's wake lock. For example, this might happen if the device is low on battery.
Examples
The following asynchronous function requests a WakeLockSentinel
object.
The request()
method is wrapped in a try...catch
statement to handle cases where the browser refuses the request for any reason.
const requestWakeLock = async () => {
try {
const wakeLock = await navigator.wakeLock.request("screen");
} catch (err) {
// The wake lock request fails - usually system-related, such as low battery.
console.log(`${err.name}, ${err.message}`);
}
};
requestWakeLock();
The screen wake lock may be revoked by the device after it has been granted.
The returned WakeLockSentinel
can be used to check the status of the lock, and/or to manually cancel a held screen wake lock.
Specifications
Specification |
---|
Screen Wake Lock API # the-request-method |
Browser compatibility
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