JavaScript bank Concurrency JavaScript / 5 questions Your progress 0 / 5 done Saved in this browser. Reset All 5 Medium 3 Hard 2 Hide done No questions match those filters. 1 What are Web Workers and how do they provide true parallelism in a single-threaded language? Medium 2 How do the main thread and a Web Worker communicate? Explain `postMessage` and structured cloning. Medium 3 Offload a CPU-heavy computation (e.g., image processing) to a Web Worker and explain the trade-offs. Hard 4 What can and cannot a Web Worker access (DOM, window, fetch, etc.)? Medium 5 Explain SharedWorker vs dedicated Worker and use cases for sharing state across multiple tabs. Hard ← Previous DOM & Browser Next → PWA