php实现图片延时加载的方法:在到达指定加载图片位置时,用data-src属性值替换img的src属性值即可,如【imgs[i].src = imgs[i].getAttribute('data-src');】。
在到达指定加载图片位置时,用data-src的属性值替换img的src的属性值即可,这个时候img就会去请求资源。
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imgs[i].src = imgs[i].getAttribute('data-src');
代码实现:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>图片懒加载</title> <style> img { display: block; width: 100%; height: 300px; margin-bottom: 20px; } </style> </head> <body> <img data-src="./images/1.jpg" alt=""> <img data-src="./images/2.jpg" alt=""> <img data-src="./images/3.jpg" alt=""> <img data-src="./images/4.jpg" alt=""> <img data-src="./images/5.jpg" alt=""> <img data-src="./images/6.jpg" alt=""> <img data-src="./images/7.jpg" alt=""> <img data-src="./images/8.jpg" alt=""> <img data-src="./images/9.jpg" alt=""> <img data-src="./images/10.jpg" alt=""> <img data-src="./images/1.jpg" alt=""> <img data-src="./images/2.jpg" alt=""> </body> <script> var imgs = document.querySelectorAll('img'); //offsetTop是元素与offsetParent的距离,循环获取直到页面顶部 function getTop(e) { var T = e.offsetTop; while(e = e.offsetParent) { T += e.offsetTop; } return T; } function lazyLoad(imgs) { var H = document.documentElement.clientHeight;//获取可视区域高度 var S = document.documentElement.scrollTop || document.body.scrollTop; for (var i = 0; i < imgs.length; i++) { if (H + S > getTop(imgs[i])) { imgs[i].src = imgs[i].getAttribute('data-src'); } } } window.onload = window.onscroll = function () { //onscroll()在滚动条滚动的时候触发 lazyLoad(imgs); } </script> </html>