picLazyLoad Realizes Picture Delay Loading of Includes Background Picture

As shown below:

/**
 * picLazyLoad  Picture delay loading, including background picture 
 * $(img).picLazyLoad({...})
 * data-original  Preload picture address 
 * alon
 */
;(function($){
  $.fn.imgLazyLoad = function(settings){
    var $this = $(this),
      _winScrollTop = 0,
      _winHeight = $(window).height();
    settings = $.extend({
      threshold: 0, //  Advance height loading 
      placeholder: 'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC',
      callback:function(){}
    }, settings||{});
    //  Perform lazy loading pictures 
    lazyLoadPic();
    //  Scroll trigger map change 
    $(window).on('scroll',function(){
      _winScrollTop = document.documentElement.scrollTop || window.pageYOffset || document.body.scrollTop;
      lazyLoadPic();
    });
    //  Load pictures lazily 
    function lazyLoadPic(){
      $this.each(function(){
        var $self = $(this);
        if($self.is('img')){
          if($self.attr('data-original')){
            var _offsetTop = $self.offset().top;
            if((_offsetTop - settings.threshold) <= (_winHeight + _winScrollTop)){
              $self.attr('src',$self.attr('data-original'));
              $self.removeAttr('data-original');
              $self.removeClass('loadH');
              settings.callback($self);
            }
          }
        }else{
          if($self.attr('data-original')){//  Default placeholder picture 
            if($self.css('background-image') == 'none'){
              $self.css('background-image','url('+settings.placeholder+')');
            }
            var _offsetTop = $self.offset().top;
            if((_offsetTop - settings.threshold) <= (_winHeight + _winScrollTop)){
              $self.css('background-image','url('+$self.attr('data-original')+')');
              $self.removeAttr('data-original');
              settings.callback($self);
            }
          }
        }
      });
    }
  }
})(Zepto);

Call

$('img').imgLazyLoad({callback:function(data){
 
 })