Ленивая загрузка для элементов

Ленивая загрузка div

Пример

<script>
$(document).ready(function(){
   $(window).scroll(lazyload);
   lazyload();
});

function lazyload(){
   var wt = $(window).scrollTop();    //* top of the window
   var wb = wt + $(window).height();  //* bottom of the window

   $('#video').each(function(){
      var ot = $(this).offset().top;  //* top of object (i.e. advertising div)
      var ob = ot + $(this).height(); //* bottom of object

      if(!$(this).attr('loaded') && wt<=ob && wb >= ot){
         $(this).html('<iframe width="560" height="315" src="https://www.youtube.com/embed/41Ts4f1vuP0" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="">');
         $(this).attr('loaded',true);
      }
   });
}
</script>