title: WebSocket inside a WebWorker - UI Thread still blocking
body: <p>i'm using WebSockets to send data from my node.js server to my clients. Since the data can be kind of large, the UI thread used to block, so no user interaction or video playing was possible during the data was received. That's when i stumbled over WebWorkers, and i also managed to get them work together with WebSockets.</p>
  
  <p>app.js:</p>
  
  <pre><code>...
  
  var worker = new Worker('worker.js');
  
  worker.addEventListener('message', function(e) {
      console.log('Worker said: ', e.data);
  }, false);
  
  worker.postMessage('init');
  
  ...
  </code></pre>
  
  <p>worker.js:</p>
  
  <pre><code>function initWebSocket() {
  
  var connection = new WebSocket('ws://host:port', ['soap', 'xmpp']);
  
  connection.onopen = function () {
      connection.send('Ping'); // Send the message 'Ping' to the server
  };
  
  // Log errors
  connection.onerror = function (error) {
    console.log('WebSocket Error ' + error);
  };
  
  // Log messages from the server
  connection.onmessage = function (e) {
    console.log('Server: ' + e.data);
    //self.postMessage('Worker received : ' + e.data);
  };
  
  };
  
  self.addEventListener('message', function(e) {
  switch (e.data) {
      case 'init':
          initWebSocket();
          break;
      default:
          self.postMessage('Unknown command: ' + e.data);
      };
  }, false);
  </code></pre>
  
  <p>All i'm doing so far is receive the data. Of course, later on i intend to do more stuff with it. But my problem is: The UI thread is still blocking when large files arrive. Did i get something wrong here?</p>
  
  <p>UPDATE:</p>
  
  <p>Actually, i have to revise my previous comment. Obviously chrome had cached some of my files i was sending before, so i didn't realize the problem starts already with files way smaller than 300MB (currently, i'm testing a 50MB file). The ui blocks until the file has been completly received. What i'm currently doing is the following: I'm loading an index page with a video playing. Also, on the same page, i put a button which starts a worker. The worker does send an xhr request to the server and gets a 50MB file. So i just dismissed WebSockets for the sake of it. What's happening when i click the button: The video freezes until the complete data has been received. When i do the same and let the worker just calculate numbers in a for-loop, the video keeps playing. So it seems to have something to work with using the network, but not specifically WebSockets. Is it possible that WebWorkers just can't work with network stuff?</p>