title: Failed to execute 'postMessage' on 'DedicatedWorkerGlobalScope': The provided value cannot be converted to a sequence
body: <p>I'm getting the following error </p>
  
  <blockquote>
    <p>Uncaught TypeError: Failed to execute 'postMessage' on
    'DedicatedWorkerGlobalScope': The provided value cannot be converted
    to a sequence.</p>
  </blockquote>
  
  <p>on this line in a webworker:</p>
  
  <pre><code>postMessage("hi", "http://localhost:8000");
  </code></pre>
  
  <p>(in fact, that is the entirety of the webworker).</p>
  
  <p>The base file contains:</p>
  
  <pre><code>var myWorker = new Worker("test.js");
  myWorker.onmessage = function (e) {
      console.log('Message received from worker');
  };
  </code></pre>
  
  <p>I'm not sure which value it's complaining about and I'm not sure what it means for it to be converted to a "sequence".</p>