Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var goog = {
      Timer: {
        defaultTimerObject: window
      },
      global: window,
      bind: function(fn, context) {
        return fn.bind(context);
      }
    };
    
    goog.Timer.getSetImmediate_ = function() {
      // Introduced and currently only supported by IE10.
      if (typeof goog.global['setImmediate'] === 'function') {
        return goog.bind(goog.global['setImmediate'], goog.global);
      }
      // Create a private message channel and use it to postMessage empty messages
      // to ourselves.
      var Channel = goog.global['MessageChannel'];
      // If MessageChannel is not available and we are in a browser, implement
      // an iframe based polyfill in browsers that have postMessage and
      // document.createEvent. The latter excludes IE8 because it has a synchronous
      // postMessage implementation.
      if (typeof Channel === 'undefined' && typeof window !== 'undefined' &&
          window.postMessage && document.createEvent) {
        /** @constructor */
        Channel = function() {
          // Make an empty, invisible iframe.
          var iframe = document.createElement('iframe');
          iframe.style.display = 'none';
          iframe.src = '';
          document.body.appendChild(iframe);
          var win = iframe.contentWindow;
          var doc = win.document;
          doc.open();
          doc.write('');
          doc.close();
          var message = 'callImmediate' + Math.random();
          var origin = win.location.protocol + '//' + win.location.host;
          iframe.contentWindow.onmessage = goog.bind(function(e) {
            // Validate origin and message to make sure that this message was
            // intended for us.
            if (e.origin != origin && e.data != message) {
              return;
            }
            this['port1'].onmessage();
          }, this);
          this['port1'] = {};
          this['port2'] = {
            postMessage: function() {
              win.postMessage(message, origin);
            }
          };
        };
      }
      if (typeof Channel !== 'undefined') {
        var channel = new Channel();
        // Use a fifo linked list to call callbacks in the right order.
        var head = {};
        var tail = head;
        channel['port1'].onmessage = function() {
          head = head.next;
          var cb = head.cb;
          head.cb = null;
          cb();
        };
        return function(cb) {
          tail.next = {
            cb: cb
          };
          tail = tail.next;
          channel['port2'].postMessage(0);
        };
      }
      // Implementation for IE6-8. Script elements fires an asynchronous
      // onreadystatechange event when inserted into the DOM.
      if (typeof document !== 'undefined' && 'onreadystatechange' in
          document.createElement('script')) {
        return function(cb) {
          var script = document.createElement('script');
          script.onreadystatechange = function() {
            // Clean up and run the callback.
            script.onreadystatechange = null;
            script.parentNode.removeChild(script);
            script = null;
            cb();
            cb = null;
          };
          document.documentElement.appendChild(script);
        };
      }
      // Fall back to setTimeout with 0. In browsers this creates a delay of 5ms
      // or more.
      return function(cb) {
        goog.global.setTimeout(cb, 0);
      }
    };
    
    goog.Timer.callImmediate = function(listener, opt_handler) {
      var callback = listener;
      if (opt_handler) {
        callback = goog.bind(listener, opt_handler);
      }
      if (!goog.Timer.setImmediate_) {
        goog.Timer.setImmediate_ = goog.Timer.getSetImmediate_();
      }
      goog.Timer.setImmediate_(callback);
    };
  };
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

// async test
goog.Timer.callImmediate(function() {
  deferred.resolve();
});

// async test
setTimeout(function() {
  deferred.resolve();
}, 0)

Compare results of other browsers

Revisions

You can edit these tests or add even more tests to this page by appending /edit to the URL. Here’s a list of current revisions for this page:

• Revision 1: published by Malte on 13th February 2013
• Revision 2: published on 13th February 2013
• Revision 4: published on 14th February 2013
• Revision 5: published by Malte on 18th February 2013

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