圖片懶加載插件，親測好用。代碼如下。
電腦pc端
(function($, window) {
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
};
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");
} else {
if (++counter > settings.failure_limit) {
return false;
}
}
});
}
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);
}
elements = $(elements).filter("[data-" + settings.data_attribute + "]");
/* 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(event) {
return update();
});
}
this.each(function() {
var self = this;
var $self = $(self);
self.loaded = false;
/* When appear is triggered load original image. */
$self.one("appear", function() {
if (!this.loaded) {
if (settings.appear) {
var elements_left = elements.length;
settings.appear.call(self, elements_left, settings);
}
$("<img />").bind("load", function() {
$self.hide().attr("src", $self.data(settings.data_attribute))[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.data(settings.data_attribute));
}
});
/* When wanted event is triggered load original image */
/* by triggering appear. */
if (0 !== settings.event.indexOf("scroll")) {
$self.bind(settings.event, function(event) {
if (!self.loaded) {
$self.trigger("appear");
}
});
}
});
/* Check if something appears when window is resized. */
$window.bind("resize", function(event) {
update();
});
/* Force initial check if images should appear. */
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.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();
};
$.inviewport = function(element, settings) {
return !$.rightofscreen(element, settings) && !$.leftofscreen(element, settings) && !$.belowthefold(element, settings) && !$.abovethetop(element, settings);
};
/* Custom selectors for your convenience. */
/* Use as $("img:below-the-fold").something() */
$.extend($.expr[':'], {
"below-the-fold": function(a) {
return $.belowthefold(a, {
threshold: 0
});
},
"above-the-top": function(a) {
return !$.belowthefold(a, {
threshold: 0
});
},
"right-of-screen": function(a) {
return $.rightoffold(a, {
threshold: 0
});
},
"left-of-screen": function(a) {
return !$.rightoffold(a, {
threshold: 0
});
},
"in-viewport": function(a) {
return !$.inviewport(a, {
threshold: 0
});
},
/* Maintain BC for couple of versions. */
"above-the-fold": function(a) {
return !$.belowthefold(a, {
threshold: 0
});
},
"right-of-fold": function(a) {
return $.rightoffold(a, {
threshold: 0
});
},
"left-of-fold": function(a) {
return !$.rightoffold(a, {
threshold: 0
});
}
});
// 圖片緩載
$.imgloading = {
loading: function() {
$("img.lazy").lazyload({
skip_invisible: false,
effect: 'fadeIn',
failure_limit: 20,
threshold: 2000,
load: function() {
$(this).removeClass('lazy');
if ($(this).hasClass('square')) {
if ($(this).height() != $(this).width()) {
$(this).height($(this).width());
}else{
$(this).removeClass('square');
}
}
}
});
}
};
})(jQuery, window);
調用示例
//圖片懶加載
function img_lazyload(){
$("img.lazy_load").lazyload({
effect : "fadeIn", //淡入效果
skip_invisible : false
})
}
img_lazyload()
手機wap端
(function($) {
$.fn.lazyload = function(options) {
var settings = {
threshold : 0,
failure_limit : 0,
event : "scroll",
effect : "show",
container : window,
skip_invisible : true
};
if(options) {
/* Maintain BC for a couple of version. */
if (null !== options.failurelimit) {
options.failure_limit = options.failurelimit;
delete options.failurelimit;
}
$.extend(settings, options);
}
/* Fire one scroll event per scroll. Not one scroll event per image. */
var elements = this;
if (0 == settings.event.indexOf("scroll")) {
$(settings.container).bind(settings.event, function(event) {
var counter = 0;
elements.each(function() {
if (settings.skip_invisible && !$(this).is(":visible")) return;
if ($.abovethetop(this, settings) ||
$.leftofbegin(this, settings)) {
/* Nothing. */
} else if (!$.belowthefold(this, settings) &&
!$.rightoffold(this, settings)) {
$(this).trigger("appear");
} else {
if (++counter > settings.failure_limit) {
return false;
}
}
});
/* Remove image from array so it is not looped next time. */
var temp = $.grep(elements, function(element) {
return !element.loaded;
});
elements = $(temp);
});
}
this.each(function() {
var self = this;
self.loaded = false;
/* When appear is triggered load original image. */
$(self).one("appear", function() {
if (!this.loaded) {
$("<img />")
.bind("load", function() {
$(self)
.hide()
.attr("src", $(self).data("original"))
[settings.effect](settings.effectspeed);
self.loaded = true;
})
.attr("src", $(self).data("original"));
};
});
/* When wanted event is triggered load original image */
/* by triggering appear. */
if (0 != settings.event.indexOf("scroll")) {
$(self).bind(settings.event, function(event) {
if (!self.loaded) {
$(self).trigger("appear");
}
});
}
});
/* Force initial check if images should appear. */
$(settings.container).trigger(settings.event);
return this;
};
/* Convenience methods in jQuery namespace. */
/* Use as $.belowthefold(element, {threshold : 100, container : window}) */
$.belowthefold = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).height() + $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top + $(settings.container).height();
}
return fold <= $(element).offset().top - settings.threshold;
};
$.rightoffold = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).width() + $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left + $(settings.container).width();
}
return fold <= $(element).offset().left - settings.threshold;
};
$.abovethetop = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollTop();
} else {
var fold = $(settings.container).offset().top;
}
return fold >= $(element).offset().top + settings.threshold + $(element).height();
};
$.leftofbegin = function(element, settings) {
if (settings.container === undefined || settings.container === window) {
var fold = $(window).scrollLeft();
} else {
var fold = $(settings.container).offset().left;
}
return fold >= $(element).offset().left + settings.threshold + $(element).width();
};
/* Custom selectors for your convenience. */
/* Use as $("img:below-the-fold").something() */
$.extend($.expr[':'], {
"below-the-fold" : function(a) { return $.belowthefold(a, {threshold : 0, container: window}) },
"above-the-fold" : function(a) { return !$.belowthefold(a, {threshold : 0, container: window}) },
"right-of-fold" : function(a) { return $.rightoffold(a, {threshold : 0, container: window}) },
"left-of-fold" : function(a) { return !$.rightoffold(a, {threshold : 0, container: window}) }
});
})(jQuery);
調用示例
//圖片懶加載
function img_lazyload(){
$("img.lazy_load").lazyload({
threshold : 0,
effect : "fadeIn", //淡入效果
skip_invisible : false
})
}
img_lazyload()