圖片懶載入imgLazyLoading.js詳解

//懒加载对象目标代码  //引用本地js  

jQuery.fn.extend({ delayLoading: function (a) { function g(d) { var b, c; if (a.container === undefined || a.container === window) { b = $(window).scrollTop(); c = $(window).height() + $(window).scrollTop() } else { b = $(a.container).offset().top; c = $(a.container).offset().top + $(a.container).height() } return d.offset().top + d.height() + a.beforehand >= b && c >= d.offset().top - a.beforehand } function h(d) { var b, c; if (a.container === undefined || a.container === window) { b = $(window).scrollLeft(); c = $(window).width() + $(window).scrollLeft() } else { b = $(a.container).offset().left; c = $(a.container).offset().left + $(a.container).width() } return d.offset().left + d.width() + a.beforehand >= b && c >= d.offset().left - a.beforehand } function f() { e.filter("img[" + a.imgSrcAttr + "]").each(function (d, b) { if ($(b).attr(a.imgSrcAttr) !== undefined && $(b).attr(a.imgSrcAttr) !== null && $(b).attr(a.imgSrcAttr) !== "" && g($(b)) && h($(b))) { var c = new Image; c.onload = function () { $(b).attr("src", c.src); a.duration !== 0 && $(b).hide().fadeIn(a.duration); $(b).removeAttr(a.imgSrcAttr); a.success($(b)) }; c.onerror = function () { $(b).attr("src", a.errorImg); $(b).removeAttr(a.imgSrcAttr); a.error($(b)) }; c.src = $(b).attr(a.imgSrcAttr) } }) } a = jQuery.extend({ defaultImg: "", errorImg: "", imgSrcAttr: "originalSrc", beforehand: 0, event: "scroll", duration: "normal", container: window, success: function () { }, error: function () { } }, a || {}); if (a.errorImg === undefined || a.errorImg === null || a.errorImg === "")a.errorImg = a.defaultImg; var e = $(this); if (e.attr("src") === undefined || e.attr("src") === null || e.attr("src") === "")e.attr("src", a.defaultImg); f(); $(a.container).bind(a.event, function () { f() }) } });

$(function () { $("img").delayLoading({ //defaultImg: "__PUBLIC__/images/img/loading.gif", // 预加载前显示的图片 errorImg: "", // 读取图片错误时替换图片(默认：与defaultImg一样) imgSrcAttr: "originalSrc", // 记录图片路径的属性(默认：originalSrc，页面img的src属性也要替换为originalSrc) beforehand: 0, // 预先提前多少像素加载图片(默认：0) event: "scroll", // 触发加载图片事件(默认：scroll) duration: "normal", // 三种预定淡出(入)速度之一的字符串("slow", "normal", or "fast")或表示动画时长的毫秒数值(如：1000),默认:"normal" container: window, // 对象加载的位置容器(默认：window) success: function (imgObj) { }, // 加载图片成功后的回调函数(默认：不执行任何操作) error: function (imgObj) { } // 加载图片失败后的回调函数(默认：不执行任何操作) }); });