https://thepma.org/wp-content/themes/optimizewp/assets/js/modules/plugins/jquery.waitforimages.js?ver=7.1

1/*
2 * waitForImages 1.4.2
3 * -------------------
4 * Provides a callback when all images have loaded in your given selector.
5 * https://github.com/alexanderdickson/waitForImages
6 *
7 * Copyright (c) 2013 Alex Dickson
8 * Licensed under the MIT license.
9 */
10(function ($) {
11    // Namespace all events.
12    var eventNamespace = 'waitForImages';
13
14    // CSS properties which contain references to images.
15    $.waitForImages = {
16        hasImageProperties: ['backgroundImage', 'listStyleImage', 'borderImage', 'borderCornerImage']
17    };
18
19    // Custom selector to find `img` elements that have a valid `src` attribute and have not already loaded.
20    $.expr[':'].uncached = function (obj) {
21        // Ensure we are dealing with an `img` element with a valid `src` attribute.
22        if (!$(obj).is('img[src!=""]')) {
23            return false;
24        }
25
26        // Firefox's `complete` property will always be `true` even if the image has not been downloaded.
27        // Doing it this way works in Firefox.
28        var img = new Image();
29        img.src = obj.src;
30        return !img.complete;
31    };
32
33    $.fn.waitForImages = function (finishedCallback, eachCallback, waitForAll) {
34
35        var allImgsLength = 0;
36        var allImgsLoaded = 0;
37
38        // Handle options object.
39        if ($.isPlainObject(arguments[0])) {
40            waitForAll = arguments[0].waitForAll;
41            eachCallback = arguments[0].each;
42			// This must be last as arguments[0]
43			// is aliased with finishedCallback.
44            finishedCallback = arguments[0].finished;
45        }
46
47        // Handle missing callbacks.
48        finishedCallback = finishedCallback || $.noop;
49        eachCallback = eachCallback || $.noop;
50
51        // Convert waitForAll to Boolean
52        waitForAll = !! waitForAll;
53
54        // Ensure callbacks are functions.
55        if (!$.isFunction(finishedCallback) || !$.isFunction(eachCallback)) {
56            throw new TypeError('An invalid callback was supplied.');
57        }
58
59        return this.each(function () {
60            // Build a list of all imgs, dependent on what images will be considered.
61            var obj = $(this);
62            var allImgs = [];
63            // CSS properties which may contain an image.
64            var hasImgProperties = $.waitForImages.hasImageProperties || [];
65            // To match `url()` references.
66            // Spec: http://www.w3.org/TR/CSS2/syndata.html#value-def-uri
67            var matchUrl = /url\(\s*(['"]?)(.*?)\1\s*\)/g;
68
69            if (waitForAll) {
70
71                // Get all elements (including the original), as any one of them could have a background image.
72                obj.find('*').andSelf().each(function () {
73                    var element = $(this);
74
75                    // If an `img` element, add it. But keep iterating in case it has a background image too.
76                    if (element.is('img:uncached')) {
77                        allImgs.push({
78                            src: element.attr('src'),
79                            element: element[0]
80                        });
81                    }
82
83                    $.each(hasImgProperties, function (i, property) {
84                        var propertyValue = element.css(property);
85                        var match;
86
87                        // If it doesn't contain this property, skip.
88                        if (!propertyValue) {
89                            return true;
90                        }
91
92                        // Get all url() of this element.
93                        while (match = matchUrl.exec(propertyValue)) {
94                            allImgs.push({
95                                src: match[2],
96                                element: element[0]
97                            });
98                        }
99                    });
100                });
101            } else {
102                // For images only, the task is simpler.
103                obj.find('img:uncached')
104                    .each(function () {
105                    allImgs.push({
106                        src: this.src,
107                        element: this
108                    });
109                });
110            }
111
112            allImgsLength = allImgs.length;
113            allImgsLoaded = 0;
114
115            // If no images found, don't bother.
116            if (allImgsLength === 0) {
117                finishedCallback.call(obj[0]);
118            }
119
120            $.each(allImgs, function (i, img) {
121
122                var image = new Image();
123
124                // Handle the image loading and error with the same callback.
125                $(image).bind('load.' + eventNamespace + ' error.' + eventNamespace, function (event) {
126                    allImgsLoaded++;
127
128                    // If an error occurred with loading the image, set the third argument accordingly.
129                    eachCallback.call(img.element, allImgsLoaded, allImgsLength, event.type == 'load');
130
131                    if (allImgsLoaded == allImgsLength) {
132                        finishedCallback.call(obj[0]);
133                        return false;

134                    }
135
136                });
137
138                image.src = img.src;
139            });
140        });
141    };
142}(jQuery));