mszynka/index.html

## index.html
<html>
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta charset="utf-8">
  </head>
  <body>
    <img class="lazy"><noscript><img src="images/test1.png"></noscript>
    <script src="script.js"></script>
  </body>
</html>

## script.js
var _createClass = (function () {
  function defineProperties(target, props) {
    for (var i = 0; i < props.length; i++) {
      var descriptor = props[i];
      descriptor.enumerable = descriptor.enumerable || false;
      descriptor.configurable = true;
      if ('value' in descriptor) descriptor.writable = true;
      Object.defineProperty(target, descriptor.key, descriptor);
    }
  }
  return function (Constructor, protoProps, staticProps) {
    if (protoProps) defineProperties(Constructor.prototype, protoProps);
    if (staticProps) defineProperties(Constructor, staticProps);
    return Constructor;
  };
}) ();

function _classCallCheck(instance, Constructor) {
  if (!(instance instanceof Constructor)) {
    throw new TypeError('Cannot call a class as a function');
  }
}

var LazyImage = (function () {
  function LazyImage(DOMImage) {
    _classCallCheck(this, LazyImage);
    this._image = new Image();
    this._domImage = DOMImage;
    var div = document.createElement('div');
    div.innerHTML = this._domImage.nextSibling.innerHTML;
    this._imageSrc = div.getElementsByTagName('img') [0].src;
    div.remove();
  }
  _createClass(LazyImage, [
    {
      key: 'load',
      value: function load() {
        var self = this;
        this._image.addEventListener('load', function (element) {
          self._domImage.src = this.src;
        });
        this._image.src = this._imageSrc;
      }
    }
  ]);
  return LazyImage;
}) ();

function lazyLoadImages(cssClass) {
  var images = document.getElementsByClassName(cssClass);
  for (var i = 0; i < images.length; i++) {
    var limg = new LazyImage(images[i]);
    limg.load();
  }
}
	<html>
	<head>
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<meta charset="utf-8">
	</head>
	<body>
	<img class="lazy"><noscript><img src="images/test1.png"></noscript>
	<script src="script.js"></script>
	</body>
	</html>
	var _createClass = (function () {
	function defineProperties(target, props) {
	for (var i = 0; i < props.length; i++) {
	var descriptor = props[i];
	descriptor.enumerable = descriptor.enumerable \|\| false;
	descriptor.configurable = true;
	if ('value' in descriptor) descriptor.writable = true;
	Object.defineProperty(target, descriptor.key, descriptor);
	}
	}
	return function (Constructor, protoProps, staticProps) {
	if (protoProps) defineProperties(Constructor.prototype, protoProps);
	if (staticProps) defineProperties(Constructor, staticProps);
	return Constructor;
	};
	}) ();

	function _classCallCheck(instance, Constructor) {
	if (!(instance instanceof Constructor)) {
	throw new TypeError('Cannot call a class as a function');
	}
	}

	var LazyImage = (function () {
	function LazyImage(DOMImage) {
	_classCallCheck(this, LazyImage);
	this._image = new Image();
	this._domImage = DOMImage;
	var div = document.createElement('div');
	div.innerHTML = this._domImage.nextSibling.innerHTML;
	this._imageSrc = div.getElementsByTagName('img') [0].src;
	div.remove();
	}
	_createClass(LazyImage, [
	{
	key: 'load',
	value: function load() {
	var self = this;
	this._image.addEventListener('load', function (element) {
	self._domImage.src = this.src;
	});
	this._image.src = this._imageSrc;
	}
	}
	]);
	return LazyImage;
	}) ();

	function lazyLoadImages(cssClass) {
	var images = document.getElementsByClassName(cssClass);
	for (var i = 0; i < images.length; i++) {
	var limg = new LazyImage(images[i]);
	limg.load();
	}
	}