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JavaScript Web Workers

April 5, 2026

Web Workers

Run scripts in background threads without blocking UI.

Worker Example

// main.js
let worker = new Worker("worker.js");
worker.postMessage({start: true});

worker.onmessage = function(e) {
    console.log("Result:", e.data);
};

// worker.js
self.onmessage = function(e) {
    let result = 0;
    for (let i = 0; i < 100000000; i++) {
        result += i;
    }
    self.postMessage(result);
};

Key Points

  • No DOM access in workers.
  • Communication via postMessage().
  • Separate global scope (self).
  • Ideal for heavy computations.
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