https://www.st-electron.com/frontend/js/lazyload/setup.lazyload.js

1$(function(){
2    var lazyloadDefault = {
3        'lazyload': 'enable',
4        'lazyloadImage': '/frontend/images/lazyload/img/loading.gif',
5        'lazyloadEffect': true,
6        'lazyloadBgcolor': '#ccc',
7        'lazyloadImgWidth': '100%',
8        'lazyloadImgHeight': '100%'
9    };
10    const updteOptions = Object.assign(lazyloadDefault, $('body').data());
11
12    if (updteOptions['lazyload'] == 'enable'){
13        let loader_effect = (updteOptions['lazyloadEffect']) ? {effect: "fadeIn"} : {};
14        $('body').addClass('lazyload-active');
15        $("img:not([class*='no-lazyload']):not([class*='captcha'])").each(function(){
16            $(this).attr('data-original', $(this).attr('src'))
17            .attr('src', updteOptions['lazyloadImage'])
18            .addClass('lazyload')
19            .css({
20                'display':'block',
21                'background-color': updteOptions['lazyloadBgcolor'],
22                'width': updteOptions['lazyloadImgWidth'],
23                'height': updteOptions['lazyloadImgHeight'],
24                'object-fit': 'cover'
25            });
26        });
27        $("img.lazyload").lazyload(loader_effect);
28    }
29});