title: MIDI.js Error code:1, can't requestMIDIAccess
body: <p>I am trying to use MIDI.js to play sounds in the browser.
  <a href="https://github.com/mudcube/MIDI.js" rel="nofollow">https://github.com/mudcube/MIDI.js</a></p>
  
  <p>It works in the chrome browser on one of my computers, but not on my other one (which is a chromebook), or on the chrome browser on two of my friends computers.</p>
  
  <p>it prints to the console</p>
  
  <p>"uh-oh! Something went wrong! Error code: 1"  MIDI.js:349</p>
  
  <p>which refers to this part of MIDI.js</p>
  
  <pre><code>navigator.requestMIDIAccess(function (access) {
          plugin = access;
          output = plugin.getOutput(0);
          if (callback) callback();
      }, function (err) {
          console.log("uh-oh! Something went wrong!  Error code: " + err.code );
      });
  </code></pre>
  
  <p>i found this post which seems to be referring to the problem i'm experiencing but i'm not quite sure</p>
  
  <p><a href="https://plus.google.com/+ChrisWilson/posts/cs4J6sS9qmJ" rel="nofollow">https://plus.google.com/+ChrisWilson/posts/cs4J6sS9qmJ</a></p>
  
  <p>where it says to swap some parts of the code for some reason I couldn't understand</p>
  
  <pre><code>navigator.requestMIDIAccess( successCallback, failureCallback );
  </code></pre>
  
  <p>becomes:</p>
  
  <pre><code>navigator.requestMIDIAccess().then( successCallback, failureCallback );
  </code></pre>
  
  <p>but after replacing that part on MIDI.js 344, i get the error message</p>
  
  <p>Uncaught TypeError: Cannot call method 'then' of undefined</p>
  
  <p>Any help on how to fix this problem so it works in all browsers, or at least all chrome browsers, would be greatly appreciated. Thankyou</p>