function lazyload(event) {
  for (var i = n; i < imgNum; iPP) {
    if (img.eq(i).offset().top < parseInt($(window).height()) + parseInt($(window).scrollTop())) {
      if (img.eq(i).attr("src") == "../images/loading/xxx.svg") {
        var src = img.eq(i).attr("data-src");
        img.eq(i).attr("src", src);

        n = i + 1;
      }
    }
  }
}

when the original movie is finished, the LOADING will be replaced into the original film
, but I want him to replace it into the original film not directly, but with a fadeIn effect
, but I believe that this is not Juqery.. So adding fadeIn () seems to be useful?