HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>self.close</title>
</head>
<body>
  <button id="run" type="button">Run job</button>
  <pre id="out">Waiting...</pre>
  <script>
    var code = [
      "self.onmessage = function (e) {",
      "  var result = Number(e.data) * 2;",
      "  self.postMessage(result);",
      "  self.close();",
      "};"
    ].join("\n");
    var url = URL.createObjectURL(new Blob([code], { type: "application/javascript" }));
    var worker = new Worker(url);
    var out = document.getElementById("out");

    worker.onmessage = function (e) {
      out.textContent = "result ready\n" + e.data + "\n(worker closed itself)";
      URL.revokeObjectURL(url);
    };

    document.getElementById("run").addEventListener("click", function () {
      worker.postMessage(21);
    });
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

Worker close() — graceful exit (Try It)