Images lazy load

jQuery.yangLazyLoad.js

;(function($, window, document){
    $.yangLazyLoad = function(){
        var img = $('img[data-src]');
        img.each(function(){
          this.src = 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC';
        })
        $(document).scroll(function(){
            img.each(function(){
                var _this = this;
                var top = $(_this).offset().top;
                var scrollTop = $(document).scrollTop();
                var wHeight = $(window).height();
                if(wHeight + scrollTop >= top){
                  var url = $(_this).attr('data-src');
                  $(_this).attr('src', url);
                }
            })            
        })
    }
}(jQuery, window, document))