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

The query() method of the LockManager interface returns a Promise that resolves with an object that contains information about held and pending locks.


var promise<LockManagerSnapshot> = LockManager.query()



Return value

A Promise that resolves with a LockManagerSnapshot containing the following properties.

  • held: An array of Lock objects for held locks.
  • pending: An array of Lock objects for pending lock requests.


const state = await navigator.locks.query();
for (const lock of state.held) {
  console.log(`held lock: name ${lock.name}, mode ${lock.mode}`);
for (const request of state.pending) {
  console.log(`requested lock: name ${request.name}, mode ${request.mode}`);


Specification Status Comment
Web Locks API
The definition of 'query()' in that specification.
Draft Initial definition.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic support
Chrome Full support 69Edge ? Firefox ? IE ? Opera Full support 56Safari ? WebView Android Full support 69Chrome Android Full support 69Edge Mobile ? Firefox Android ? Opera Android Full support 56Safari iOS ? Samsung Internet Android ?


Full support  
Full support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.

Document Tags and Contributors

Contributors to this page: jpmedley
Last updated by: jpmedley,