The global performance property returns a Performance object, which can be used to gather performance information about the context it is called in (window or worker).

Performance entries are per context. If you create a mark on the main thread (or other worker), you cannot see it in a worker thread, and vice versa.

A Performance object offering access to performance and timing-related information for the context it is called on (window or worker).

The following table provides an overview about the availability of the performance APIs in window and worker contexts.