<!-- BEGIN COPY / PASTE -->
        // Main script
        const worker = new Worker('worker.js');

        // Send data to the worker
        const dataToSend = { key: 'value' };
        worker.postMessage(dataToSend);

        // Receive data from the worker
        worker.addEventListener('message', (event) => {
            console.log('Received from worker:', event.data);
        });

        // Worker script (worker.js)
        self.addEventListener('message', (event) => {
            const receivedData = event.data;
            // Process data and send back
            const processedData = { ...receivedData, processed: true };
            self.postMessage(processedData);
        });
        <!-- END COPY / PASTE -->