JS延迟加载图片
图片延迟加载的JS代码。将页面的img标签中的src写成src2即可使用。
例如：
<img alt="JS推延加载图片" title="lazy image" src2="http://www.abc.com/lazeimage.jpg">
function getPosition(h) { var a = navigator.userAgent.toLowerCase(); var b = (a.indexOf("opera") != -1); var e = (a.indexOf("msie") != -1 && !b); var d = h; if (d.parentNode === null || d.style.display == "none") { return false } var l = null; var k = [ ]; var i; if (d.getBoundingClientRect) { i = d.getBoundingClientRect(); if (a.indexOf("ipad") != -1) { return { x: i.left, y: i.top } } var c = jQuery(window).scrollTop(); var f = jQuery(window).scrollLeft(); return { x: i.left + f, y: i.top + c } } else { if (document.getBoxObjectFor) { i = document.getBoxObjectFor(d); var j = (d.style.borderLeftWidth) ? parseInt(d.style.borderLeftWidth) : 0; var g = (d.style.borderTopWidth) ? parseInt(d.style.borderTopWidth) : 0; k = [i.x - j, i.y - g] } else { k = [d.offsetLeft, d.offsetTop]; l = d.offsetParent; if (l != d) { while (l) { k[0] += l.offsetLeft; k[1] += l.offsetTop; l = l.offsetParent } } if (a.indexOf("opera") != -1 || (a.indexOf("safari") != -1 && d.style.position == "absolute")) { k[0] -= document.body.offsetLeft; k[1] -= document.body.offsetTop } } } if (d.parentNode) { l = d.parentNode } else { l = null } while (l && l.tagName != "BODY" && l.tagName != "HTML") { k[0] -= l.scrollLeft; k[1] -= l.scrollTop; if (l.parentNode) { l = l.parentNode } else { l = null } } return { x: k[0], y: k[1] }}jQuery(document).ready(function lazyload() { var d = jQuery("img[src2]"); var a = function() { return jQuery(window).height() + jQuery(window).scrollTop() }; imgLoad(d, a()); var c = 150; var b = 0; jQuery(window).bind("scroll", function() { var e = Math.abs(jQuery(window).scrollTop() - b); if (e >= c) { imgLoad(d, a()); if (imgLoadStatus == 1) { b += c; imgLoadStatus = 0 } } })});var imgLoadStatus = 0;function imgLoad(b, a) { b = jQuery("img[src2]"); b.each(function() { var d = jQuery(this).attr("src2"); if (d) { var c = getPosition(jQuery(this)[0]).y; if (c <= a && (c + jQuery(this).height()) >= jQuery(window).scrollTop()) { jQuery(this).attr("src", d).removeAttr("src2") } } }); imgLoadStatus = 1};