oblank/gist:0ba8f9b4f9a4298bc7eb

## gistfile1.txt

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
    <meta name="viewport" content="width=device-width">

    <title>Promise example</title>

    <link rel="stylesheet" href="">
    <!--[if lt IE 9]>
      <script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->
  </head>

  <body>
    <h1>Promise example</h1>

    <p>Darth Vader image by <a href="https://www.flickr.com/photos/digital_stability/">Shawn Taylor</a>, published under a <a href="https://creativecommons.org/licenses/by-nc-nd/2.0/">Attribution-NonCommercial-NoDerivs 2.0 Generic</a> license.</p>
  </body>

  <script>

  function imgLoad(url) {
    // Create new promise with the Promise() constructor;
    // This has as its argument a function
    // with two parameters, resolve and reject
    return new Promise(function(resolve, reject) {
      // Standard XHR to load an image
      var request = new XMLHttpRequest();
      request.open('GET', url);
      request.responseType = 'blob';

      // When the request loads, check whether it was successful
      request.onload = function() {
        if (request.status === 200) {
        // If successful, resolve the promise by passing back the request response
          resolve(request.response);
        } else {
        // If it fails, reject the promise with a error message
          reject(Error('Image didn\'t load successfully; error code:' + request.statusText));
        }
      };

      request.onerror = function() {
      // Also deal with the case when the entire request fails to begin with
      // This is probably a network error, so reject the promise with an appropriate message
          reject(Error('There was a network error.'));
      };

      // Send the request
      request.send();
    });
  }

  // Get a reference to the body element, and create a new image object
  var body = document.querySelector('body');
  var myImage = new Image();

  // Call the function with the URL we want to load, but then chain the
  // promise then() method on to the end of it. This contains two callbacks
  imgLoad('myLittleVader.jpg').then(function(response) {
    // The first runs when the promise resolves, with the request.reponse
    // specified within the resolve() method.
    var imageURL = window.URL.createObjectURL(response);
    myImage.src = imageURL;
    body.appendChild(myImage);
    // The second runs when the promise
    // is rejected, and logs the Error specified with the reject() method.
  }, function(Error) {
    console.log(Error);
  });

  </script>
</html>

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
	<meta name="viewport" content="width=device-width">

	<title>Promise example</title>

	<link rel="stylesheet" href="">
	<!--[if lt IE 9]>
	<script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
	<![endif]-->
	</head>

	<body>
	<h1>Promise example</h1>

	<p>Darth Vader image by <a href="https://www.flickr.com/photos/digital_stability/">Shawn Taylor</a>, published under a <a href="https://creativecommons.org/licenses/by-nc-nd/2.0/">Attribution-NonCommercial-NoDerivs 2.0 Generic</a> license.</p>
	</body>

	<script>

	function imgLoad(url) {
	// Create new promise with the Promise() constructor;
	// This has as its argument a function
	// with two parameters, resolve and reject
	return new Promise(function(resolve, reject) {
	// Standard XHR to load an image
	var request = new XMLHttpRequest();
	request.open('GET', url);
	request.responseType = 'blob';

	// When the request loads, check whether it was successful
	request.onload = function() {
	if (request.status === 200) {
	// If successful, resolve the promise by passing back the request response
	resolve(request.response);
	} else {
	// If it fails, reject the promise with a error message
	reject(Error('Image didn\'t load successfully; error code:' + request.statusText));
	}
	};

	request.onerror = function() {
	// Also deal with the case when the entire request fails to begin with
	// This is probably a network error, so reject the promise with an appropriate message
	reject(Error('There was a network error.'));
	};

	// Send the request
	request.send();
	});
	}

	// Get a reference to the body element, and create a new image object
	var body = document.querySelector('body');
	var myImage = new Image();

	// Call the function with the URL we want to load, but then chain the
	// promise then() method on to the end of it. This contains two callbacks
	imgLoad('myLittleVader.jpg').then(function(response) {
	// The first runs when the promise resolves, with the request.reponse
	// specified within the resolve() method.
	var imageURL = window.URL.createObjectURL(response);
	myImage.src = imageURL;
	body.appendChild(myImage);
	// The second runs when the promise
	// is rejected, and logs the Error specified with the reject() method.
	}, function(Error) {
	console.log(Error);
	});

	</script>
	</html>