(function($, window, document, undefined) {
var $window = $(window);
$.fn.lazyload = function(options) {
var elements = this;
var $container;
var settings = {
threshold : 0,
failure_limit : 0,
event : "scroll",
effect : "show",
container : window,
data_attribute : "original",
skip_invisible : true,
appear : null,
load : null,
yasPath: '/web/',
yasImgDomain: 'http://analytics.yhurl.com/yas.gif',
placeholder : "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC",
try_again_css: null
};
function update() {
var counter = 0;
elements.each(function() {
var $this = $(this);
if (settings.skip_invisible && !$this.is(":visible")) {
return;
}
if ($.abovethetop(this, settings) ||
$.leftofbegin(this, settings)) {
/* Nothing. */
} else if (!$.belowthefold(this, settings) &&
!$.rightoffold(this, settings)) {
$this.trigger("appear");
/* if we found an image we'll load, reset the counter */
counter = 0;
} else {
if (++counter > settings.failure_limit) {
return false;
}
}
});
};
//add by jp, 发送图片方式跨域发送消息
function crossSend(param, callback) {
var image = new Image(1, 1);
image.src = settings.yasImgDomain + settings.yasPath + '?' + param;
image.onload = function() {
image.onload = null;
if (callback) {
callback();
}
};
};
if(options) {
/* Maintain BC for a couple of versions. */
if (undefined !== options.failurelimit) {
options.failure_limit = options.failurelimit;
delete options.failurelimit;
}
if (undefined !== options.effectspeed) {
options.effect_speed = options.effectspeed;
delete options.effectspeed;
}
$.extend(settings, options);
}
/* Cache container as jQuery as object. */
$container = (settings.container === undefined ||
settings.container === window) ? $window : $(settings.container);
/* Fire one scroll event per scroll. Not one scroll event per image. */
if (0 === settings.event.indexOf("scroll")) {
$container.bind(settings.event, function() {
return update();
});
}
this.each(function() {
var self = this;
var $self = $(self);
self.loaded = false;
/* If no src attribute given use data:uri. */
if ($self.attr("src") === undefined || $self.attr("src") === false || $self.attr("src") === '') {
if ($self.is("img")) {
$self.attr("src", settings.placeholder);
}
}
/* When appear is triggered load original image. */
$self.one("appear", function() {
//add by jp
if($self.timerid) clearTimeout($self.timerid);
//console.log("img appear, this.loaded:" + this.loaded + ", id:" + $self.attr("id"));
if (!this.loaded) {
if (settings.appear) {
var elements_left = elements.length;
settings.appear.call(self, elements_left, settings);
}
$("<img />")
//add by jp
.bind("error abort", function(){
$self.attr("src",settings.placeholder);
loadfail({info:'error'});
})
.bind("load", function() {
//add by jp, 加载超时后，不再进行加载，通过传统方式设置src，边下载边渲染
if($self.loadtimeout){
return;
}
//add by jp, 清理检测图片下载超时定时器
clearTimeout($self.timerid);
//add by jp, 上报图片加载成功事件
if( $self.attr("pfmrpt") ){
//crossImgSend('success');
}
var original = $self.attr("data-" + settings.data_attribute);
$self.hide();
if ($self.is("img")) {
$self.attr("src", original);
} else {
$self.css("background-image", "url('" + original + "')");
}
$self[settings.effect](settings.effect_speed);
self.loaded = true;
/* Remove image from array so it is not looped next time. */
var temp = $.grep(elements, function(element) {
return !element.loaded;
});
elements = $(temp);
if (settings.load) {
var elements_left = elements.length;
settings.load.call(self, elements_left, settings);
}
})
.attr("src", $self.attr("data-" + settings.data_attribute));
//add by jp , 临时保存图片url
$self.src = $self.attr("data-" + settings.data_attribute);
//add by jp , 上报图片开始加载事件
if( $self.attr("pfmrpt") && _yas && _yas.add){
//crossImgSend(,'start');
}
//add by jp, 图片加载失败或超时的处理
var loadtimeout = function(options){
//记录标识图片加载超时
$self.loadtimeout = true;
//上报图片加载超时事件
if( $self.attr("pfmrpt") && _yas && _yas.add){
options.info ; //error or timeout
//crossImgSend(settings.yasImgDomain,settings.yasPath,'fail');
}
//清除图片src取值，便于图片边下载边渲染
$self.attr("src","");
setTimeout(function(){
$self.attr("src",$self.src);
},50);
};
//add by jp, 图片加载失败或超时的处理
var loadfail = function(options){
//记录标识图片加载超时
$self.loadtimeout = true;
//上报图片加载失败事件
if( $self.attr("pfmrpt") && _yas && _yas.add){
options.info ; //error or timeout
//crossImgSend(settings.yasImgDomain,settings.yasPath,'fail');
}
var width = $self.width();
var height = $self.height();
var $tryagain = $("<div class="+settings.try_again_css+" style='background-image:url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB/AAffA0nNPuCLAAAAAElFTkSuQmCC) ;text-align: center;position:relative;width:"+width+"px;height:"+height+"px; line-height:"+height+"px'>图片打开失败,点击重新加载</div>");
// $tryagain.css("background-image",settings.placeholder);
$self.replaceWith($tryagain);
$tryagain.bind("click", function(e){
e.preventDefault();
$tryagain.replaceWith($self);
//清除图片src取值，便于图片边下载边渲染
$self.attr("src","");
setTimeout(function(){
$self.attr("src",$self.src);
},50);
});
};
//图片下载超时检测
$self.timerid = setTimeout(loadtimeout,5000);
}
});
/* When wanted event is triggered load original image */
/* by triggering appear. */
if (0 !== settings.event.indexOf("scroll")) {
$self.bind(settings.event, function() {
if (!self.loaded) {
$self.trigger("appear");
}
});
}
});
/* Check if something appears when window is resized. */
$window.bind("resize", function() {
update();
});
/* With IOS5 force loading images when navigating with back button. */
/* Non optimal workaround. */
if ((/(?:iphone|ipod|ipad).*os 5/gi).test(navigator.appVersion)) {
$window.bind("pageshow", function(event) {
if (event.originalEvent && event.originalEvent.persisted) {
elements.each(function() {
$(this).trigger("appear");
});
}
});
}
/* Force initial check if images should appear. */
$(document).ready(function() {
update();
});
return this;
};
/* Convenience methods in jQuery namespace. */
/* Use as $.belowthefold(element, {threshold : 100, container : window}) */
$.belowthefold = function(element, settings) {
var fold;
if (settings.container === undefined || settings.container === window) {
fold = (window.innerHeight ? window.innerHeight : $window.height()) + $window.scrollTop();
} else {
fold = $(settings.container).offset().top + $(settings.container).height();
}
return fold <= $(element).offset().top - settings.threshold;
};
$.rightoffold = function(element, settings) {
var fold;
if (settings.container === undefined || settings.container === window) {
fold = $window.width() + $window.scrollLeft();
} else {
fold = $(settings.container).offset().left + $(settings.container).width();
}
return fold <= $(element).offset().left - settings.threshold;
};
$.abovethetop = function(element, settings) {
var fold;
if (settings.container === undefined || settings.container === window) {
fold = $window.scrollTop();
} else {
fold = $(settings.container).offset().top;
}
return fold >= $(element).offset().top + settings.threshold + $(element).height();
};
$.leftofbegin = function(element, settings) {
var fold;
if (settings.container === undefined || settings.container === window) {
fold = $window.scrollLeft();
} else {
fold = $(settings.container).offset().left;
}
return fold >= $(element).offset().left + settings.threshold + $(element).width();
};
$.inviewport = function(element, settings) {
return !$.rightoffold(element, settings) && !$.leftofbegin(element, settings) &&
!$.belowthefold(element, settings) && !$.abovethetop(element, settings);
};
})($, window, document);