Setting up fancybox on Bitrix?

Question

fancyBox

Why doesn't fancybox for pictures work on Bitrix, I'm not ok in Bitrix, so where to start picking?
PS The code is not mine, but I need to redo it.
The only code I found:

function(n, i, _, d) {
        var s = _("html"),
            o = _(n),
            c = _(i),
            $ = _.fancybox = function() {
                $.open.apply(this, arguments)
            },
            r = navigator.userAgent.match(/msie/i),
            a = null,
            l = i.createTouch !== d,
            p = function(e) {
                return e && e.hasOwnProperty && e instanceof _
            },
            u = function(e) {
                return e && "string" === _.type(e)
            },
            E = function(e) {
                return u(e) && 0 < e.indexOf("%")
            },
            P = function(e, t) {
                var i = parseInt(e, 10) || 0;
                return t && E(e) && (i *= $.getViewport()[t] / 100), Math.ceil(i)
            },
            A = function(e, t) {
                return P(e, t) + "px"
            };
        _.extend($, {
            version: "2.1.7",
            defaults: {
                padding: 15,
                margin: 20,
                width: 800,
                height: 600,
                minWidth: 100,
                minHeight: 100,
                maxWidth: 9999,
                maxHeight: 9999,
                pixelRatio: 1,
                autoSize: !0,
                autoHeight: !1,
                autoWidth: !1,
                autoResize: !0,
                autoCenter: !l,
                fitToView: !0,
                aspectRatio: !1,
                topRatio: .5,
                leftRatio: .5,
          arrows: true,
                scrolling: "auto",
                wrapCSS: "",
                arrows: true,
                closeBtn: !0,
                closeClick: !1,
                nextClick: !1,
                mouseWheel: !0,
                autoPlay: !1,
                playSpeed: 3e3,
                preload: 3,
                modal: !1,
                loop: !0,
                ajax: {
                    dataType: "html",
                    headers: {
                        "X-fancyBox": !0
                    }
                },

Answer 1

It's written why it doesn't work