https://www.studioalphen.nl/assets/js/adsenseloader.js?v=3

1/*
2	A JavaScript plugin for lazy-loading responsive Google Adsense ads.
3	-
4	By Osvaldas Valutis, www.osvaldas.info
5	Available for use under the MIT License
6*/
7
8;(function (root, factory) {
9    const pluginName = 'adsenseLoader';
10    if (typeof define === 'function' && define.amd) define([], factory(pluginName));
11    else if (typeof exports === 'object') module.exports = factory(pluginName);
12    else root[pluginName] = factory(pluginName);
13
14}(this, function () {
15    let getAdWidth = function (ad) {
16        return parseInt(window.getComputedStyle(ad, ':before').getPropertyValue('content').slice(1, -1) || 9999);
17    };
18    let removeAdFromList = function (list, element) {
19        return list.filter(function (entry) {
20            return entry !== element;
21        });
22    };
23    'use strict';
24
25    let scriptUrl = '//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js',
26        scriptLoaded = false,
27        throttleTO = 250,
28
29        defaultOpts =
30            {
31                laziness: 1,
32                onLoad: false,
33            },
34
35        extendObj = function (defaults, options) {
36            let prop, extended = {};
37            for (prop in defaults)
38                if (Object.prototype.hasOwnProperty.call(defaults, prop))
39                    extended[prop] = defaults[prop];
40
41            for (prop in options)
42                if (Object.prototype.hasOwnProperty.call(options, prop))
43                    extended[prop] = options[prop];
44
45            return extended;
46        },
47
48        addClass = function (el, className) {
49            if (el.classList) el.classList.add(className);
50            else el.className += ' ' + className;
51        },
52
53        getOffset = function (el) {
54            const rect = el.getBoundingClientRect();
55            return {top: rect.top + document.body.scrollTop, left: rect.left + document.body.scrollLeft};
56        },
57
58        loadScript = function (url, callback) {
59            const s = document.createElement('script');
60            s.src = url;
61            s.async = true;
62            s.addEventListener('load', function () {
63                s.parentNode.removeChild(s);
64                if (typeof callback === 'function')
65                    callback();
66            });
67            document.body.appendChild(s);
68        },
69
70        throttle = function (a, b) {
71            let c, d;
72            return function () {
73                let e = this, f = arguments, g = +new Date;
74                c && g < c + a ? (clearTimeout(d), d = setTimeout(function () {
75                    c = g, b.apply(e, f)
76                }, a)) : (c = g, b.apply(e, f))
77            }
78        },
79
80        isHidden = function(el) {
81            return (el.offsetParent === null)
82        },
83
84        adsToLoad = [],
85        adsLoaded = [],
86        adsPending = [],
87
88        loadAd = function (ad) {
89            (adsbygoogle = window.adsbygoogle || []).push({});
90
91            const onLoadFn = ad._adsenseLoaderData.options.onLoad;
92            if (typeof onLoadFn === 'function') {
93                ad.querySelector('iframe').addEventListener('load', function () {
94                    onLoadFn(ad);
95                });
96            }
97        },
98        initAds = function () {
99            if (!adsToLoad.length) return true;
100
101            let winScroll = window.pageYOffset,
102                winHeight = window.innerHeight;
103
104            adsToLoad.forEach(function (ad) {
105                let offset = getOffset(ad).top,
106                    laziness = ad._adsenseLoaderData.options.laziness + 1;
107
108                // if the element is too far below || too far above
109                if (offset - winScroll > winHeight * laziness || winScroll - offset - ad.offsetHeight - (winHeight * laziness) > 0)
110                    return true;
111
112                if(isHidden(ad)) {
113                    return true;
114                }
115
116                adsToLoad = removeAdFromList(adsToLoad, ad);
117                ad._adsenseLoaderData.width = getAdWidth(ad);
118                addClass(ad.children[0], 'adsbygoogle');
119                adsLoaded.push(ad);
120
121                if (typeof adsbygoogle !== 'undefined') loadAd(ad);
122                else adsPending.push(ad);
123
124                if (!scriptLoaded) {
125                    scriptLoaded = true;
126                    loadScript(scriptUrl, function () {
127                        adsPending.forEach(loadAd);
128                    });
129                }
130            });
131        },
132        normalizeAdElement = function (ad, options) {
133            ad._adsenseLoaderData =
134                {
135                    originalHTML: ad.innerHTML,
136                    options: options
137                };
138            ad.adsenseLoader = function (method) {
139                if (method === 'destroy') {

140                    adsToLoad = removeAdFromList(adsToLoad, ad);
141                    adsLoaded = removeAdFromList(adsLoaded, ad);
142                    adsPending = removeAdFromList(adsLoaded, ad);
143                    ad.innerHTML = ad._adsenseLoaderData.originalHTML;
144                }
145            };
146            return ad;
147        };
148
149
150    window.addEventListener('scroll', throttle(throttleTO, initAds));
151
152    function Plugin(elements, options) {
153        if (typeof elements === 'string') elements = document.querySelectorAll(elements);
154        else if (typeof elements.length === 'undefined') elements = [elements];
155
156        options = extendObj(defaultOpts, options);
157
158        [].forEach.call(elements, function (entry) {
159            entry = normalizeAdElement(entry, options);
160            adsToLoad.push(entry);
161        });
162
163        this.elements = elements;
164
165        initAds();
166    }
167
168    Plugin.prototype =
169        {
170            destroy: function () {
171                this.elements.forEach(function (entry) {
172                    entry.adsenseLoader('destroy');
173                });
174            }
175        };
176
177    window.adsenseLoaderConfig = function (options) {
178        if (typeof options.scriptUrl !== 'undefined')
179            scriptUrl = options.scriptUrl;
180
181        if (typeof options.throttle !== 'undefined')
182            throttleTO = options.throttle;
183    };
184
185    return Plugin;
186}));