The Worker interface of the Web Workers API represents a background task that can be easily created and can send messages back to its creator. Creating a worker is as simple as calling the Worker() constructor and specifying a script to be run in the worker thread.
The onmessage property of the Worker interface represents an EventHandler, that is a function to be called when the message event occurs. These events are of type MessageEvent and will be called when the worker's parent receives a message (i.e. from the DedicatedWorkerGlobalScope.postMessage method.
The postMessage() method of the Worker interface sends a message to the worker's inner scope. This accepts a single parameter, which is the data to send to the worker. The data may be any value or JavaScript object handled by the structured clone algorithm, which includes cyclical references.
The terminate() method of the Worker interface immediately terminates the Worker. This does not offer the worker an opportunity to finish its operations; it is simply stopped at once.