<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>Document</title> <style> * { margin: 0; padding: 0; }
body { background: #f1f1f1; }
img { display: block; }
.waterfall .box { padding-right: 10px; padding-bottom: 10px; position: absolute; transition: left .5s, top .5s; /* background: white; */ }
.waterfall .box img { width: 250px; }
.waterfall .box p { background: white; height: 30px; line-height: 30px; }
.waterfall .box p span { font-size: 12px; color: #666; }
.waterfall .box p a { font-size: 12px; color: #444; text-decoration: none; }
.waterfall .box p a:hover { background: #e5461c; color: #fff; } </style> </head>
<body> <div class="waterfall"> <!-- (div.box>img[src="./imgs/pic ($).jpg"]+p>span{标签：}+a{明星})*50 --> <div class="box"> <img src="./imgs/pic (111).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (2).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (3).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (4).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (5).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (6).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (7).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (8).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (9).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (10).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (11).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (12).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (13).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (14).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (15).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (16).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (17).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (18).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (19).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (20).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (21).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (22).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (23).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (24).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (25).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (26).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (27).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (28).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (29).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (30).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (31).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (32).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (33).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (34).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (35).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (36).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (37).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (38).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (39).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (40).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (41).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (42).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (43).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (44).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (45).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (46).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (47).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (48).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (49).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> <div class="box"> <img src="./imgs/pic (50).jpg" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div>
</div>
<script> function waterfall() { //取得所有盒子 var boxes = document.querySelectorAll('.waterfall .box'); var boxW = boxes[0].offsetWidth var col = Math.floor(window.innerWidth / boxW); var heightArray = [];
for (var i = 0; i < boxes.length; i++) { if (i < col) { //第一行 boxes[i].style.top = 0; boxes[i].style.left = i * boxW + 'px' heightArray.push(boxes[i].offsetHeight); } else { //其他行 // 1. 找到数组的最小值 // 使用展开运算符...，将nums展开，之后，传递给Math.min(),就可以取得最小高度 var minH = Math.min(...heightArray); var minIndex = heightArray.indexOf(minH);
boxes[i].style.top = minH + 'px' boxes[i].style.left = minIndex * boxW + 'px'
heightArray[minIndex] = minH + boxes[i].offsetHeight;
} }
console.log(heightArray) }
//页面大小改变，或者是zoom改变时，会触发onresize window.onresize = window.onload = function () { //在这个事件中调用waterfall()可以保证布局发生在所有的图片下载完成之后。 waterfall() }
window.onscroll = function () { if (needLoad()) { //加载数据 loadData(); } }
function needLoad() { //返回true需要加载，返回false不需要 let lastBox = document.querySelector('.box:last-of-type');
//取得这个盒子距离可视区顶端的距离 let dist = lastBox.getBoundingClientRect().y // return dist<= window.innerHeight ? true : flase return dist <= window.innerHeight }
var start;
function loadData() { //ajax获取数据 var now = new Date(); //每次调用loadData，都取得一个当前时间 if (!start || now - start > 1000) { //start等于未定义，就是这第一次调用loadData start = now; //计时开始 let xhr = new XMLHttpRequest();
xhr.open('get', './imgs.json', true)
xhr.onload = function () { if (this.status >= 200 && this.status < 300) { //取得数据 // console.log(this.responseText) let imgs = JSON.parse(this.responseText)
//直接在修改完DOM树后，调用waterfall()，会因为图片还没下载完成导致布局的错误。 //我们需要等待这30张图片加载完成，再调用waterfall //我们只需要监听每个图片加载完成的事件，并在时间中对计数器进行自增。 //当计数器数值等于了图片总个数，说明全部加载完成。此时可以调用waterfall() var counter = 0;
imgs.forEach(img => { let pic = new Image(); //创建一个图片对象 pic.src = img.src; //将图片对象的src进行了赋值。一旦给图片对象的src赋值，浏览器就会开始下载图片
pic.onload = function () { //图片下载完成时，会触发该事件 counter++; if (counter === imgs.length) { waterfall(); } } pic.onerror = function () { //图片下载失败，会触发这个事件 counter++; if (counter === imgs.length) { waterfall(); } } })
let boxes = imgs.map(obj => ` <div class="box"> <img src="${obj.src}" alt=""> <p><span>标签：</span><a href="">明星</a></p> </div> `) boxes = boxes.join(''); // console.log(boxes); document.querySelector('.waterfall').innerHTML += boxes;
// waterfall(); } else { //出错了 } }
xhr.send() } //根据数据创建div.box的节点 }
</script>
</body>
</html>