title: jQuery Post blob object gives Uncaught TypeError: Illegal invocation
body: <p>I am trying to post a file using jQuery <code>post</code>, and get <code>TypeError: Illegal invocation</code></p>
  
  <pre><code>function fbUpload(token){
    var dataURL = canvas.toDataURL('image/jpeg', 1.0)
    var blob = dataURItoBlob(dataURL)
  
    $.post( "https://graph.facebook.com/me/photos", {
      'access_token': token,
      'source': blob
    }, function( data ) {
      console.log(data);
    });
  }
  </code></pre>
  
  <p>Could it be because of the 'blob'?</p>
  
  <p>This is working fine:</p>
  
  <pre><code>function fbUpload(token){
    var dataURL = canvas.toDataURL('image/jpeg', 1.0)
    var blob = dataURItoBlob(dataURL)
    var formData = new FormData()
    formData.append('access_token', token)
    formData.append('source', blob)
  
    var xhr = new XMLHttpRequest();
    xhr.open( 'POST', 'https://graph.facebook.com/me/photos', true )
    xhr.onload = xhr.onerror = function() {
      console.log( xhr.responseText )
    };
    xhr.send( formData )
  }
  </code></pre>