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/*!
hey, [be]Lazy.js - v1.8.2 - 2016.10.25
A fast, small and dependency free lazy load script (https://github.com/dinbror/blazy)
(c) Bjoern Klinggaard - @bklinggaard - http://dinbror.dk/blazy
*/
;
(function(root, blazy) {
if (typeof define === 'function' && define.amd) {
// AMD. Register bLazy as an anonymous module
define(blazy);
} else if (typeof exports === 'object') {
// Node. Does not work with strict CommonJS, but
// only CommonJS-like environments that support module.exports,
// like Node.
module.exports = blazy();
} else {
// Browser globals. Register bLazy on window
root.Blazy = blazy();
}
})(this, function() {
'use strict';
//private vars
var _source, _viewport, _isRetina, _supportClosest, _attrSrc = 'src', _attrSrcset = 'srcset';
// constructor
return function Blazy(options) {
//IE7- fallback for missing querySelectorAll support
if (!document.querySelectorAll) {
var s = document.createStyleSheet();
document.querySelectorAll = function(r, c, i, j, a) {
a = document.all, c = [], r = r.replace(/\[for\b/gi, '[htmlFor').split(',');
for (i = r.length; i--;) {
s.addRule(r[i], 'k:v');
for (j = a.length; j--;) a[j].currentStyle.k && c.push(a[j]);
s.removeRule(0);
}
return c;
};
}
//options and helper vars
var scope = this;
var util = scope._util = {};
util.elements = [];
util.destroyed = true;
scope.options = options || {};
scope.options.error = scope.options.error || false;
scope.options.offset = scope.options.offset || 100;
scope.options.root = scope.options.root || document;
scope.options.success = scope.options.success || false;
scope.options.selector = scope.options.selector || '.b-lazy';
scope.options.separator = scope.options.separator || '|';
scope.options.containerClass = scope.options.container;
scope.options.container = scope.options.containerClass ? document.querySelectorAll(scope.options.containerClass) : false;
scope.options.errorClass = scope.options.errorClass || 'b-error';
scope.options.breakpoints = scope.options.breakpoints || false;
scope.options.loadInvisible = scope.options.loadInvisible || false;
scope.options.successClass = scope.options.successClass || 'b-loaded';
scope.options.validateDelay = scope.options.validateDelay || 25;
scope.options.saveViewportOffsetDelay = scope.options.saveViewportOffsetDelay || 50;
scope.options.srcset = scope.options.srcset || 'data-srcset';
scope.options.src = _source = scope.options.src || 'data-src';
_supportClosest = Element.prototype.closest;
_isRetina = window.devicePixelRatio > 1;
_viewport = {};
_viewport.top = 0 - scope.options.offset;
_viewport.left = 0 - scope.options.offset;
/* public functions
************************************/
scope.revalidate = function() {
initialize(scope);
};
scope.load = function(elements, force) {
var opt = this.options;
if (elements && elements.length === undefined) {
loadElement(elements, force, opt);
} else {
each(elements, function(element) {
loadElement(element, force, opt);
});
}
};
scope.destroy = function() {
var util = scope._util;
if (scope.options.container) {
each(scope.options.container, function(object) {
unbindEvent(object, 'scroll', util.validateT);
});
}
unbindEvent(window, 'scroll', util.validateT);
unbindEvent(window, 'resize', util.validateT);
unbindEvent(window, 'resize', util.saveViewportOffsetT);
util.count = 0;
util.elements.length = 0;
util.destroyed = true;
};
//throttle, ensures that we don't call the functions too often
util.validateT = throttle(function() {
validate(scope);
}, scope.options.validateDelay, scope);
util.saveViewportOffsetT = throttle(function() {
saveViewportOffset(scope.options.offset);
}, scope.options.saveViewportOffsetDelay, scope);
saveViewportOffset(scope.options.offset);
//handle multi-served image src (obsolete)
each(scope.options.breakpoints, function(object) {
if (object.width >= window.screen.width) {
_source = object.src;
return false;
}
});
// start lazy load
setTimeout(function() {
initialize(scope);
}); // "dom ready" fix
};
/* Private helper functions
************************************/
function initialize(self) {
var util = self._util;
// First we create an array of elements to lazy load
util.elements = toArray(self.options);
util.count = util.elements.length;
// Then we bind resize and scroll events if not already binded
if (util.destroyed) {
util.destroyed = false;
if (self.options.container) {
each(self.options.container, function(object) {
bindEvent(object, 'scroll', util.validateT);
});
}
bindEvent(window, 'resize', util.saveViewportOffsetT);
bindEvent(window, 'resize', util.validateT);
bindEvent(window, 'scroll', util.validateT);
}
// And finally, we start to lazy load.
validate(self);
}
function validate(self) {
var util = self._util;
for (var i = 0; i < util.count; i++) {
var element = util.elements[i];
if (elementInView(element, self.options) || hasClass(element, self.options.successClass)) {
self.load(element);
util.elements.splice(i, 1);
util.count--;
i--;
}
}
if (util.count === 0) {
self.destroy();
}
}
function elementInView(ele, options) {
var rect = ele.getBoundingClientRect();
if(options.container && _supportClosest){
// Is element inside a container?
var elementContainer = ele.closest(options.containerClass);
if(elementContainer){
var containerRect = elementContainer.getBoundingClientRect();
// Is container in view?
if(inView(containerRect, _viewport)){
var top = containerRect.top - options.offset;
var right = containerRect.right + options.offset;
var bottom = containerRect.bottom + options.offset;
var left = containerRect.left - options.offset;
var containerRectWithOffset = {
top: top > _viewport.top ? top : _viewport.top,
right: right < _viewport.right ? right : _viewport.right,
bottom: bottom < _viewport.bottom ? bottom : _viewport.bottom,
left: left > _viewport.left ? left : _viewport.left
};
// Is element in view of container?
return inView(rect, containerRectWithOffset);
} else {
return false;
}
}
}
return inView(rect, _viewport);
}
function inView(rect, viewport){
// Intersection
return rect.right >= viewport.left &&
rect.bottom >= viewport.top &&
rect.left <= viewport.right &&
rect.top <= viewport.bottom;
}
function loadElement(ele, force, options) {
// if element is visible, not loaded or forced
if (!hasClass(ele, options.successClass) && (force || options.loadInvisible || (ele.offsetWidth > 0 && ele.offsetHeight > 0))) {
var dataSrc = getAttr(ele, _source) || getAttr(ele, options.src); // fallback to default 'data-src'
if (dataSrc) {
var dataSrcSplitted = dataSrc.split(options.separator);
var src = dataSrcSplitted[_isRetina && dataSrcSplitted.length > 1 ? 1 : 0];
var srcset = getAttr(ele, options.srcset);
var isImage = equal(ele, 'img');
var parent = ele.parentNode;
var isPicture = parent && equal(parent, 'picture');
// Image or background image
if (isImage || ele.src === undefined) {
var img = new Image();
// using EventListener instead of onerror and onload
// due to bug introduced in chrome v50
// (https://productforums.google.com/forum/#!topic/chrome/p51Lk7vnP2o)
var onErrorHandler = function() {
if (options.error) options.error(ele, "invalid");
addClass(ele, options.errorClass);
unbindEvent(img, 'error', onErrorHandler);
unbindEvent(img, 'load', onLoadHandler);
};
var onLoadHandler = function() {
// Is element an image
if (isImage) {
if(!isPicture) {
handleSources(ele, src, srcset);
}
// or background-image
} else {
ele.style.backgroundImage = 'url("' + src + '")';
}
itemLoaded(ele, options);
unbindEvent(img, 'load', onLoadHandler);
unbindEvent(img, 'error', onErrorHandler);
};
// Picture element
if (isPicture) {
img = ele; // Image tag inside picture element wont get preloaded
each(parent.getElementsByTagName('source'), function(source) {
handleSource(source, _attrSrcset, options.srcset);
});
}
bindEvent(img, 'error', onErrorHandler);
bindEvent(img, 'load', onLoadHandler);
handleSources(img, src, srcset); // Preload
} else { // An item with src like iframe, unity games, simpel video etc
ele.src = src;
itemLoaded(ele, options);
}
} else {
// video with child source
if (equal(ele, 'video')) {
each(ele.getElementsByTagName('source'), function(source) {
handleSource(source, _attrSrc, options.src);
});
ele.load();
itemLoaded(ele, options);
} else {
if (options.error) options.error(ele, "missing");
addClass(ele, options.errorClass);
}
}
}
}
function itemLoaded(ele, options) {
addClass(ele, options.successClass);
if (options.success) options.success(ele);
// cleanup markup, remove data source attributes
removeAttr(ele, options.src);
removeAttr(ele, options.srcset);
each(options.breakpoints, function(object) {
removeAttr(ele, object.src);
});
}
function handleSource(ele, attr, dataAttr) {
var dataSrc = getAttr(ele, dataAttr);
if (dataSrc) {
setAttr(ele, attr, dataSrc);
removeAttr(ele, dataAttr);
}
}
function handleSources(ele, src, srcset){
if(srcset) {
setAttr(ele, _attrSrcset, srcset); //srcset
}
ele.src = src; //src
}
function setAttr(ele, attr, value){
ele.setAttribute(attr, value);
}
function getAttr(ele, attr) {
return ele.getAttribute(attr);
}
function removeAttr(ele, attr){
ele.removeAttribute(attr);
}
function equal(ele, str) {
return ele.nodeName.toLowerCase() === str;
}
function hasClass(ele, className) {
return (' ' + ele.className + ' ').indexOf(' ' + className + ' ') !== -1;
}
function addClass(ele, className) {
if (!hasClass(ele, className)) {
ele.className += ' ' + className;
}
}
function toArray(options) {
var array = [];
var nodelist = (options.root).querySelectorAll(options.selector);
for (var i = nodelist.length; i--; array.unshift(nodelist[i])) {}
return array;
}
function saveViewportOffset(offset) {
_viewport.bottom = (window.innerHeight || document.documentElement.clientHeight) + offset;
_viewport.right = (window.innerWidth || document.documentElement.clientWidth) + offset;
}
function bindEvent(ele, type, fn) {
if (ele.attachEvent) {
ele.attachEvent && ele.attachEvent('on' + type, fn);
} else {
ele.addEventListener(type, fn, { capture: false, passive: true });
}
}
function unbindEvent(ele, type, fn) {
if (ele.detachEvent) {
ele.detachEvent && ele.detachEvent('on' + type, fn);
} else {
ele.removeEventListener(type, fn, { capture: false, passive: true });
}
}
function each(object, fn) {
if (object && fn) {
var l = object.length;
for (var i = 0; i < l && fn(object[i], i) !== false; i++) {}
}
}
function throttle(fn, minDelay, scope) {
var lastCall = 0;
return function() {
var now = +new Date();
if (now - lastCall < minDelay) {
return;
}
lastCall = now;
fn.apply(scope, arguments);
};
}
});
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