https://www.vitawebtv.it/wp-content/plugins/embedpress/assets/js/lazy-load.js?ver=1769782854

1/**
2 * EmbedPress Lazy Load
3 * 
4 * Custom lazy loading implementation for iframe embeds using Intersection Observer API
5 * Only loads iframes when they're about to enter the viewport
6 * 
7 * @package EmbedPress
8 * @since 4.0.0
9 */
10
11(function() {
12    'use strict';
13
14    // Check if Intersection Observer is supported
15    if (!('IntersectionObserver' in window)) {
16        console.warn('EmbedPress Lazy Load: IntersectionObserver not supported, loading all iframes immediately');
17        loadAllIframes();
18        return;
19    }
20
21    /**
22     * Get dynamic root margin based on viewport height
23     * This prevents lazy loading from triggering immediately on short pages
24     * Uses 50% of viewport height or 200px, whichever is smaller
25     */
26    function getObserverConfig() {
27        const viewportHeight = window.innerHeight;
28        const margin = Math.min(200, Math.max(50, viewportHeight * 0.25));
29
30        return {
31            rootMargin: margin + 'px 0px',
32            threshold: 0.01
33        };
34    }
35
36    const observerConfig = getObserverConfig();
37
38    /**
39     * Callback function when iframe placeholder enters viewport
40     */
41    function onIntersection(entries, observer) {
42        entries.forEach(function(entry) {
43            if (entry.isIntersecting) {
44                const placeholder = entry.target;
45                loadIframe(placeholder);
46                observer.unobserve(placeholder);
47            }
48        });
49    }
50
51    /**
52     * Load the actual iframe from placeholder
53     */
54    function loadIframe(placeholder) {
55        const iframeSrc = placeholder.getAttribute('data-ep-lazy-src');
56
57        if (!iframeSrc) {
58            console.warn('EmbedPress Lazy Load: No data-ep-lazy-src found on placeholder');
59            return;
60        }
61
62        // Create iframe element
63        const iframe = document.createElement('iframe');
64        iframe.src = iframeSrc;
65
66        // Copy style
67        const iframeStyle = placeholder.getAttribute('data-ep-iframe-style');
68        if (iframeStyle) {
69            iframe.setAttribute('style', iframeStyle);
70        }
71
72        // Copy all data-ep-iframe-* attributes
73        Array.from(placeholder.attributes).forEach(function(attr) {
74            if (attr.name.startsWith('data-ep-iframe-')) {
75                const iframeAttr = attr.name.replace('data-ep-iframe-', '');
76                if (iframeAttr !== 'style') {
77                    iframe.setAttribute(iframeAttr, attr.value);
78                }
79            }
80        });
81
82        // Copy class (remove placeholder class)
83        if (placeholder.hasAttribute('class')) {
84            const classes = placeholder.getAttribute('class').replace(/ep-lazy-iframe-placeholder/g, '').trim();
85            if (classes) {
86                iframe.setAttribute('class', classes);
87            }
88        }
89
90        // Copy other important attributes
91        ['data-emid', 'data-embedpress-content', 'data-embed-type', 'title'].forEach(function(attr) {
92            if (placeholder.hasAttribute(attr)) {
93                iframe.setAttribute(attr, placeholder.getAttribute(attr));
94            }
95        });
96
97        // Replace placeholder with iframe
98        if (placeholder.parentNode) {
99            placeholder.parentNode.replaceChild(iframe, placeholder);
100        }
101    }
102
103    /**
104     * Fallback: Load all iframes immediately (for unsupported browsers)
105     */
106    function loadAllIframes() {
107        const placeholders = document.querySelectorAll('.ep-lazy-iframe-placeholder');
108        placeholders.forEach(function(placeholder) {
109            // Add 2 second delay before loading iframe
110            loadIframe(placeholder);
111        });
112    }
113
114    /**
115     * Initialize lazy loading
116     */
117    function initLazyLoad() {
118        const placeholders = document.querySelectorAll('.ep-lazy-iframe-placeholder');
119        
120        if (placeholders.length === 0) {
121            return;
122        }
123
124        // Create observer
125        const observer = new IntersectionObserver(onIntersection, observerConfig);
126
127        // Observe all placeholders
128        placeholders.forEach(function(placeholder) {
129            observer.observe(placeholder);
130        });
131    }
132
133    /**
134     * Run on DOM ready
135     */
136    if (document.readyState === 'loading') {
137        // Add 2 second delay before initializing lazy load
138        setTimeout(initLazyLoad, 1000);
139    } else {
140        setTimeout(initLazyLoad, 1000);
141    }
142
143    /**
144     * Re-initialize for dynamically added content (e.g., AJAX loaded content)
145     */
146    window.epReinitLazyLoad = initLazyLoad;
147
148})();
149