https://economymiddleeast.com/wp-content/plugins/a3-lazy-load/assets/js/jquery.lazyloadxt.srcset.js?ver=2.7.9

1/*! Lazy Load XT v1.1.0 2016-01-12
2 * http://ressio.github.io/lazy-load-xt
3 * (C) 2016 RESS.io
4 * Licensed under MIT */
5
6(function ($, window, document, undefined) {
7    var options = $.lazyLoadXT,
8        srcsetSupport = (function () {
9            return 'srcset' in (new Image());
10        })(),
11        reUrl = /^\s*(\S*)/,
12        reWidth = /\S\s+(\d+)w/,
13        reHeight = /\S\s+(\d+)h/,
14        reDpr = /\S\s+([\d\.]+)x/,
15        infty = [0, Infinity],
16        one = [0, 1],
17        srcsetOptions = {
18            srcsetAttr: 'data-srcset',
19            srcsetExtended: true,
20            srcsetBaseAttr: 'data-srcset-base',
21            srcsetExtAttr: 'data-srcset-ext'
22        },
23        viewport = {
24            w: 0,
25            h: 0,
26            x: 0
27        },
28        property,
29        limit;
30
31    for (property in srcsetOptions) {
32        if (options[property] === undefined) {
33            options[property] = srcsetOptions[property];
34        }
35    }
36    options.selector += ',img[' + options.srcsetAttr + '],source[' + options.srcsetAttr + ']';
37
38    function mathFilter(array, action) {
39        return Math[action].apply(null, $.map(array, function (item) {
40            return item[property];
41        }));
42    }
43
44    function compareMax(item) {
45        return item[property] >= viewport[property] || item[property] === limit;
46    }
47
48    function compareMin(item) {
49        return item[property] === limit;
50    }
51
52    function parseSrcset($el) {
53        var srcset = $el.attr(options.srcsetAttr);
54
55        if (!srcset) {
56            return false;
57        }
58
59        var list = $.map(srcset.replace(/(\s[\d.]+[whx]),/g, '$1 @,@ ').split(' @,@ '), function (item) {
60            return {
61                url: reUrl.exec(item)[1],
62                w: parseFloat((reWidth.exec(item) || infty)[1]),
63                h: parseFloat((reHeight.exec(item) || infty)[1]),
64                x: parseFloat((reDpr.exec(item) || one)[1])
65            };
66        });
67
68        if (!list.length) {
69            return false;
70        }
71
72        var documentElement = document.documentElement,
73            whx,
74            src;
75
76        viewport = {
77            w: window.innerWidth || documentElement.clientWidth,
78            h: window.innerHeight || documentElement.clientHeight,
79            x: window.devicePixelRatio || 1
80        };
81
82        // Notice for DOMtastic users: currently $.grep method is not implemented in DOMtastic
83
84        for (whx in viewport) {
85            property = whx;
86            limit = mathFilter(list, 'max');
87            list = $.grep(list, compareMax);
88        }
89
90        for (whx in viewport) {
91            property = whx;
92            limit = mathFilter(list, 'min');
93            list = $.grep(list, compareMin);
94        }
95
96        src = list[0].url;
97
98        if (options.srcsetExtended) {
99            src = ($el.attr(options.srcsetBaseAttr) || '') + src + ($el.attr(options.srcsetExtAttr) || '');
100        }
101
102        return src;
103    }
104
105    $(document).on('lazyshow', 'img', function (e, $el) {
106        var srcset = $el.attr(options.srcsetAttr);
107
108        if (srcset) {
109            if (!options.srcsetExtended && srcsetSupport) {
110                $el.attr('srcset', srcset);
111                $el.attr('data-srcset', '');
112            } else {
113                $el.lazyLoadXT.srcAttr = parseSrcset;
114            }
115        }
116    });
117
118    $(document).on('lazyshow', 'source', function (e, $el) {
119        $(this).removeClass('lazy-hidden');
120        
121        var srcset = $el.attr(options.srcsetAttr);
122
123        if (srcset) {
124            if (!options.srcsetExtended && srcsetSupport) {
125                $el.attr('srcset', srcset);
126                $el.attr('data-srcset', '');
127            } else {
128                $el.lazyLoadXT.srcAttr = parseSrcset;
129            }
130        }
131    });
132
133})(window.jQuery || window.Zepto || window.$, window, document);