LazyLoad basic Replace.

lazyload.js

(function(){

  var initImages =
  function(node,selector){
    var images = node.querySelector(selector);
    [].foreach.call(images,function(el){
      el.src = el.attr('data-lazyload');
      el.classList.remove(selector);
    });
  };

  return function(){
    initImages(document,'bc-lazy-load');
    return initImages;
  };
  
}());