Edit file File name : jquery.lazy.js Content :/*! * jQuery & Zepto Lazy - v1.7.10 * http://jquery.eisbehr.de/lazy/ * * Copyright 2012 - 2018, Daniel 'Eisbehr' Kern * * Dual licensed under the MIT and GPL-2.0 licenses: * http://www.opensource.org/licenses/mit-license.php * http://www.gnu.org/licenses/gpl-2.0.html * * $("img.lazy").lazy(); */ ;(function(window, undefined) { "use strict"; // noinspection JSUnresolvedVariable /** * library instance - here and not in construct to be shorter in minimization * @return void */ var $ = window.jQuery || window.Zepto, /** * unique plugin instance id counter * @type {number} */ lazyInstanceId = 0, /** * helper to register window load for jQuery 3 * @type {boolean} */ windowLoaded = false; /** * make lazy available to jquery - and make it a bit more case-insensitive :) * @access public * @type {function} * @param {object} settings * @return {LazyPlugin} */ $.fn.Lazy = $.fn.lazy = function(settings) { return new LazyPlugin(this, settings); }; /** * helper to add plugins to lazy prototype configuration * @access public * @type {function} * @param {string|Array} names * @param {string|Array|function} [elements] * @param {function} loader * @return void */ $.Lazy = $.lazy = function(names, elements, loader) { // make second parameter optional if ($.isFunction(elements)) { loader = elements; elements = []; } // exit here if parameter is not a callable function if (!$.isFunction(loader)) { return; } // make parameters an array of names to be sure names = $.isArray(names) ? names : [names]; elements = $.isArray(elements) ? elements : [elements]; var config = LazyPlugin.prototype.config, forced = config._f || (config._f = {}); // add the loader plugin for every name for (var i = 0, l = names.length; i < l; i++) { if (config[names[i]] === undefined || $.isFunction(config[names[i]])) { config[names[i]] = loader; } } // add forced elements loader for (var c = 0, a = elements.length; c < a; c++) { forced[elements[c]] = names[0]; } }; /** * contains all logic and the whole element handling * is packed in a private function outside class to reduce memory usage, because it will not be created on every plugin instance * @access private * @type {function} * @param {LazyPlugin} instance * @param {object} config * @param {object|Array} items * @param {object} events * @param {string} namespace * @return void */ function _executeLazy(instance, config, items, events, namespace) { /** * a helper to trigger the 'onFinishedAll' callback after all other events * @access private * @type {number} */ var _awaitingAfterLoad = 0, /** * visible content width * @access private * @type {number} */ _actualWidth = -1, /** * visible content height * @access private * @type {number} */ _actualHeight = -1, /** * determine possibly detected high pixel density * @access private * @type {boolean} */ _isRetinaDisplay = false, /** * dictionary entry for better minimization * @access private * @type {string} */ _afterLoad = 'afterLoad', /** * dictionary entry for better minimization * @access private * @type {string} */ _load = 'load', /** * dictionary entry for better minimization * @access private * @type {string} */ _error = 'error', /** * dictionary entry for better minimization * @access private * @type {string} */ _img = 'img', /** * dictionary entry for better minimization * @access private * @type {string} */ _src = 'src', /** * dictionary entry for better minimization * @access private * @type {string} */ _srcset = 'srcset', /** * dictionary entry for better minimization * @access private * @type {string} */ _sizes = 'sizes', /** * dictionary entry for better minimization * @access private * @type {string} */ _backgroundImage = 'background-image'; /** * initialize plugin * bind loading to events or set delay time to load all items at once * @access private * @return void */ function _initialize() { // detect actual device pixel ratio // noinspection JSUnresolvedVariable _isRetinaDisplay = window.devicePixelRatio > 1; // prepare all initial items items = _prepareItems(items); // if delay time is set load all items at once after delay time if (config.delay >= 0) { setTimeout(function() { _lazyLoadItems(true); }, config.delay); } // if no delay is set or combine usage is active bind events if (config.delay < 0 || config.combined) { // create unique event function events.e = _throttle(config.throttle, function(event) { // reset detected window size on resize event if (event.type === 'resize') { _actualWidth = _actualHeight = -1; } // execute 'lazy magic' _lazyLoadItems(event.all); }); // create function to add new items to instance events.a = function(additionalItems) { additionalItems = _prepareItems(additionalItems); items.push.apply(items, additionalItems); }; // create function to get all instance items left events.g = function() { // filter loaded items before return in case internal filter was not running until now return (items = $(items).filter(function() { return !$(this).data(config.loadedName); })); }; // create function to force loading elements events.f = function(forcedItems) { for (var i = 0; i < forcedItems.length; i++) { // only handle item if available in current instance // use a compare function, because Zepto can't handle object parameter for filter // var item = items.filter(forcedItems[i]); /* jshint loopfunc: true */ var item = items.filter(function() { return this === forcedItems[i]; }); if (item.length) { _lazyLoadItems(false, item); } } }; // load initial items _lazyLoadItems(); // bind lazy load functions to scroll and resize event // noinspection JSUnresolvedVariable $(config.appendScroll).on('scroll.' + namespace + ' resize.' + namespace, events.e); } } /** * prepare items before handle them * @access private * @param {Array|object|jQuery} items * @return {Array|object|jQuery} */ function _prepareItems(items) { // fetch used configurations before loops var defaultImage = config.defaultImage, placeholder = config.placeholder, imageBase = config.imageBase, srcsetAttribute = config.srcsetAttribute, loaderAttribute = config.loaderAttribute, forcedTags = config._f || {}; // filter items and only add those who not handled yet and got needed attributes available items = $(items).filter(function() { var element = $(this), tag = _getElementTagName(this); return !element.data(config.handledName) && (element.attr(config.attribute) || element.attr(srcsetAttribute) || element.attr(loaderAttribute) || forcedTags[tag] !== undefined); }) // append plugin instance to all elements .data('plugin_' + config.name, instance); for (var i = 0, l = items.length; i < l; i++) { var element = $(items[i]), tag = _getElementTagName(items[i]), elementImageBase = element.attr(config.imageBaseAttribute) || imageBase; // generate and update source set if an image base is set if (tag === _img && elementImageBase && element.attr(srcsetAttribute)) { element.attr(srcsetAttribute, _getCorrectedSrcSet(element.attr(srcsetAttribute), elementImageBase)); } // add loader to forced element types if (forcedTags[tag] !== undefined && !element.attr(loaderAttribute)) { element.attr(loaderAttribute, forcedTags[tag]); } // set default image on every element without source if (tag === _img && defaultImage && !element.attr(_src)) { element.attr(_src, defaultImage); } // set placeholder on every element without background image else if (tag !== _img && placeholder && (!element.css(_backgroundImage) || element.css(_backgroundImage) === 'none')) { element.css(_backgroundImage, "url('" + placeholder + "')"); } } return items; } /** * the 'lazy magic' - check all items * @access private * @param {boolean} [allItems] * @param {object} [forced] * @return void */ function _lazyLoadItems(allItems, forced) { // skip if no items where left if (!items.length) { // destroy instance if option is enabled if (config.autoDestroy) { // noinspection JSUnresolvedFunction instance.destroy(); } return; } var elements = forced || items, loadTriggered = false, imageBase = config.imageBase || '', srcsetAttribute = config.srcsetAttribute, handledName = config.handledName; // loop all available items for (var i = 0; i < elements.length; i++) { // item is at least in loadable area if (allItems || forced || _isInLoadableArea(elements[i])) { var element = $(elements[i]), tag = _getElementTagName(elements[i]), attribute = element.attr(config.attribute), elementImageBase = element.attr(config.imageBaseAttribute) || imageBase, customLoader = element.attr(config.loaderAttribute); // is not already handled if (!element.data(handledName) && // and is visible or visibility doesn't matter (!config.visibleOnly || element.is(':visible')) && ( // and image source or source set attribute is available (attribute || element.attr(srcsetAttribute)) && ( // and is image tag where attribute is not equal source or source set (tag === _img && (elementImageBase + attribute !== element.attr(_src) || element.attr(srcsetAttribute) !== element.attr(_srcset))) || // or is non image tag where attribute is not equal background (tag !== _img && elementImageBase + attribute !== element.css(_backgroundImage)) ) || // or custom loader is available customLoader)) { // mark element always as handled as this point to prevent double handling loadTriggered = true; element.data(handledName, true); // load item _handleItem(element, tag, elementImageBase, customLoader); } } } // when something was loaded remove them from remaining items if (loadTriggered) { items = $(items).filter(function() { return !$(this).data(handledName); }); } } /** * load the given element the lazy way * @access private * @param {object} element * @param {string} tag * @param {string} imageBase * @param {function} [customLoader] * @return void */ function _handleItem(element, tag, imageBase, customLoader) { // increment count of items waiting for after load ++_awaitingAfterLoad; // extended error callback for correct 'onFinishedAll' handling var errorCallback = function() { _triggerCallback('onError', element); _reduceAwaiting(); // prevent further callback calls errorCallback = $.noop; }; // trigger function before loading image _triggerCallback('beforeLoad', element); // fetch all double used data here for better code minimization var srcAttribute = config.attribute, srcsetAttribute = config.srcsetAttribute, sizesAttribute = config.sizesAttribute, retinaAttribute = config.retinaAttribute, removeAttribute = config.removeAttribute, loadedName = config.loadedName, elementRetina = element.attr(retinaAttribute); // handle custom loader if (customLoader) { // on load callback var loadCallback = function() { // remove attribute from element if (removeAttribute) { element.removeAttr(config.loaderAttribute); } // mark element as loaded element.data(loadedName, true); // call after load event _triggerCallback(_afterLoad, element); // remove item from waiting queue and possibly trigger finished event // it's needed to be asynchronous to run after filter was in _lazyLoadItems setTimeout(_reduceAwaiting, 1); // prevent further callback calls loadCallback = $.noop; }; // bind error event to trigger callback and reduce waiting amount element.off(_error).one(_error, errorCallback) // bind after load callback to element .one(_load, loadCallback); // trigger custom loader and handle response if (!_triggerCallback(customLoader, element, function(response) { if(response) { element.off(_load); loadCallback(); } else { element.off(_error); errorCallback(); } })) { element.trigger(_error); } } // handle images else { // create image object var imageObj = $(new Image()); // bind error event to trigger callback and reduce waiting amount imageObj.one(_error, errorCallback) // bind after load callback to image .one(_load, function() { // remove element from view element.hide(); // set image back to element // do it as single 'attr' calls, to be sure 'src' is set after 'srcset' if (tag === _img) { element.attr(_sizes, imageObj.attr(_sizes)) .attr(_srcset, imageObj.attr(_srcset)) .attr(_src, imageObj.attr(_src)); } else { if(element.attr("data-full-bg-image")){ element.css(_backgroundImage, element.attr("data-full-bg-image")); }else{ element.css(_backgroundImage, "url('" + imageObj.attr(_src) + "')"); } } // bring it back with some effect! element[config.effect](config.effectTime); // remove attribute from element if (removeAttribute) { element.removeAttr(srcAttribute + ' ' + srcsetAttribute + ' ' + retinaAttribute + ' ' + config.imageBaseAttribute); // only remove 'sizes' attribute, if it was a custom one if (sizesAttribute !== _sizes) { element.removeAttr(sizesAttribute); } } // mark element as loaded element.data(loadedName, true); // call after load event _triggerCallback(_afterLoad, element); // cleanup image object imageObj.remove(); // remove item from waiting queue and possibly trigger finished event _reduceAwaiting(); }); // set sources // do it as single 'attr' calls, to be sure 'src' is set after 'srcset' var imageSrc = (_isRetinaDisplay && elementRetina ? elementRetina : element.attr(srcAttribute)) || ''; imageObj.attr(_sizes, element.attr(sizesAttribute)) .attr(_srcset, element.attr(srcsetAttribute)) .attr(_src, imageSrc ? imageBase + imageSrc : null); // call after load even on cached image imageObj.complete && imageObj.trigger(_load); // jshint ignore : line } } /** * check if the given element is inside the current viewport or threshold * @access private * @param {object} element * @return {boolean} */ function _isInLoadableArea(element) { var elementBound = element.getBoundingClientRect(), direction = config.scrollDirection, threshold = config.threshold, vertical = // check if element is in loadable area from top ((_getActualHeight() + threshold) > elementBound.top) && // check if element is even in loadable are from bottom (-threshold < elementBound.bottom), horizontal = // check if element is in loadable area from left ((_getActualWidth() + threshold) > elementBound.left) && // check if element is even in loadable area from right (-threshold < elementBound.right); if (direction === 'vertical') { return vertical; } else if (direction === 'horizontal') { return horizontal; } return vertical && horizontal; } /** * receive the current viewed width of the browser * @access private * @return {number} */ function _getActualWidth() { return _actualWidth >= 0 ? _actualWidth : (_actualWidth = $(window).width()); } /** * receive the current viewed height of the browser * @access private * @return {number} */ function _getActualHeight() { return _actualHeight >= 0 ? _actualHeight : (_actualHeight = $(window).height()); } /** * get lowercase tag name of an element * @access private * @param {object} element * @returns {string} */ function _getElementTagName(element) { return element.tagName.toLowerCase(); } /** * prepend image base to all srcset entries * @access private * @param {string} srcset * @param {string} imageBase * @returns {string} */ function _getCorrectedSrcSet(srcset, imageBase) { if (imageBase) { // trim, remove unnecessary spaces and split entries var entries = srcset.split(','); srcset = ''; for (var i = 0, l = entries.length; i < l; i++) { srcset += imageBase + entries[i].trim() + (i !== l - 1 ? ',' : ''); } } return srcset; } /** * helper function to throttle down event triggering * @access private * @param {number} delay * @param {function} callback * @return {function} */ function _throttle(delay, callback) { var timeout, lastExecute = 0; return function(event, ignoreThrottle) { var elapsed = +new Date() - lastExecute; function run() { lastExecute = +new Date(); // noinspection JSUnresolvedFunction callback.call(instance, event); } timeout && clearTimeout(timeout); // jshint ignore : line if (elapsed > delay || !config.enableThrottle || ignoreThrottle) { run(); } else { timeout = setTimeout(run, delay - elapsed); } }; } /** * reduce count of awaiting elements to 'afterLoad' event and fire 'onFinishedAll' if reached zero * @access private * @return void */ function _reduceAwaiting() { --_awaitingAfterLoad; // if no items were left trigger finished event if (!items.length && !_awaitingAfterLoad) { _triggerCallback('onFinishedAll'); } } /** * single implementation to handle callbacks, pass element and set 'this' to current instance * @access private * @param {string|function} callback * @param {object} [element] * @param {*} [args] * @return {boolean} */ function _triggerCallback(callback, element, args) { if ((callback = config[callback])) { // jQuery's internal '$(arguments).slice(1)' are causing problems at least on old iPads // below is shorthand of 'Array.prototype.slice.call(arguments, 1)' callback.apply(instance, [].slice.call(arguments, 1)); return true; } return false; } // if event driven or window is already loaded don't wait for page loading if (config.bind === 'event' || windowLoaded) { _initialize(); } // otherwise load initial items and start lazy after page load else { // noinspection JSUnresolvedVariable $(window).on(_load + '.' + namespace, _initialize); } } /** * lazy plugin class constructor * @constructor * @access private * @param {object} elements * @param {object} settings * @return {object|LazyPlugin} */ function LazyPlugin(elements, settings) { /** * this lazy plugin instance * @access private * @type {object|LazyPlugin|LazyPlugin.prototype} */ var _instance = this, /** * this lazy plugin instance configuration * @access private * @type {object} */ _config = $.extend({}, _instance.config, settings), /** * instance generated event executed on container scroll or resize * packed in an object to be referenceable and short named because properties will not be minified * @access private * @type {object} */ _events = {}, /** * unique namespace for instance related events * @access private * @type {string} */ _namespace = _config.name + '-' + (++lazyInstanceId); // noinspection JSUndefinedPropertyAssignment /** * wrapper to get or set an entry from plugin instance configuration * much smaller on minify as direct access * @access public * @type {function} * @param {string} entryName * @param {*} [value] * @return {LazyPlugin|*} */ _instance.config = function(entryName, value) { if (value === undefined) { return _config[entryName]; } _config[entryName] = value; return _instance; }; // noinspection JSUndefinedPropertyAssignment /** * add additional items to current instance * @access public * @param {Array|object|string} items * @return {LazyPlugin} */ _instance.addItems = function(items) { _events.a && _events.a($.type(items) === 'string' ? $(items) : items); // jshint ignore : line return _instance; }; // noinspection JSUndefinedPropertyAssignment /** * get all left items of this instance * @access public * @returns {object} */ _instance.getItems = function() { return _events.g ? _events.g() : {}; }; // noinspection JSUndefinedPropertyAssignment /** * force lazy to load all items in loadable area right now * by default without throttle * @access public * @type {function} * @param {boolean} [useThrottle] * @return {LazyPlugin} */ _instance.update = function(useThrottle) { _events.e && _events.e({}, !useThrottle); // jshint ignore : line return _instance; }; // noinspection JSUndefinedPropertyAssignment /** * force element(s) to load directly, ignoring the viewport * @access public * @param {Array|object|string} items * @return {LazyPlugin} */ _instance.force = function(items) { _events.f && _events.f($.type(items) === 'string' ? $(items) : items); // jshint ignore : line return _instance; }; // noinspection JSUndefinedPropertyAssignment /** * force lazy to load all available items right now * this call ignores throttling * @access public * @type {function} * @return {LazyPlugin} */ _instance.loadAll = function() { _events.e && _events.e({all: true}, true); // jshint ignore : line return _instance; }; // noinspection JSUndefinedPropertyAssignment /** * destroy this plugin instance * @access public * @type {function} * @return undefined */ _instance.destroy = function() { // unbind instance generated events // noinspection JSUnresolvedFunction, JSUnresolvedVariable $(_config.appendScroll).off('.' + _namespace, _events.e); // noinspection JSUnresolvedVariable $(window).off('.' + _namespace); // clear events _events = {}; return undefined; }; // start using lazy and return all elements to be chainable or instance for further use // noinspection JSUnresolvedVariable _executeLazy(_instance, _config, elements, _events, _namespace); return _config.chainable ? elements : _instance; } /** * settings and configuration data * @access public * @type {object|*} */ LazyPlugin.prototype.config = { // general name : 'lazy', chainable : true, autoDestroy : true, bind : 'load', threshold : 500, visibleOnly : false, appendScroll : window, scrollDirection : 'both', imageBase : null, defaultImage : 'data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==', placeholder : null, delay : -1, combined : false, // attributes attribute : 'data-src', srcsetAttribute : 'data-srcset', sizesAttribute : 'data-sizes', retinaAttribute : 'data-retina', loaderAttribute : 'data-loader', imageBaseAttribute : 'data-imagebase', removeAttribute : true, handledName : 'handled', loadedName : 'loaded', // effect effect : 'show', effectTime : 0, // throttle enableThrottle : true, throttle : 250, // callbacks beforeLoad : undefined, afterLoad : undefined, onError : undefined, onFinishedAll : undefined }; // register window load event globally to prevent not loading elements // since jQuery 3.X ready state is fully async and may be executed after 'load' $(window).on('load', function() { windowLoaded = true; }); })(window); Save