https://www.museummartena.nl/themes/museummartena2021/js/modalhistory.js

1var ModalHistory = {
2	modalStack: [],
3	popOnClose: false,
4	closeOnPop: false,
5	originalTitle: document.title,
6	closeCallback: function (modalObject) {},
7	openModal: function (modalObject, url, title, rel) {
8		if ('pushState' in history) {
9			history.pushState({}, title || document.title, url);
10			this.modalStack.push({ modalObject: modalObject, title: title, rel: rel || 'stack' });
11			if (title)
12				document.title = title;
13		}
14	},
15	updateTitle: function () {
16		document.title = this.modalStack.length ? (this.modalStack[this.modalStack.length-1].title || this.originalTitle) : this.originalTitle;
17	},
18	closeModal: function () {
19		if (!this.closeOnPop) {
20			this.popOnClose = true;
21			history.back();
22			this.modalStack.pop();
23			this.updateTitle();
24		} else {
25			this.closeOnPop = false;
26		}
27	},
28	closeAll: function () {
29		while (this.modalStack.length > 0) {
30			this.popOnClose = true;
31			this.modalStack.pop();
32			history.back();
33		}
34	},
35	popModal: function () {
36		var modal;
37
38		if (!this.popOnClose) {
39			if (this.modalStack.length) {
40				this.closeOnPop = true;
41				modal = this.modalStack.pop();
42				this.closeCallback(modal);
43				this.updateTitle();
44			}
45		} else {
46			this.popOnClose = false;
47		}
48	}
49};
50$(window).on('popstate', function () {
51	ModalHistory.popModal();
52});
53
54ModalHistory.closeCallback = function (state) {
55	state.modalObject.hide();
56}