核心思想
随机产生规定范围内的整数，然后再产生相同范围内的整数，两者相同时，则暂停。
所用知识
Math.random() * num: 产生从0到num的随机数
Math.floor(): 向下取整
简单的DOM操作等
技术扩展
扩展人数
添加停止键等
效果
代码如下
html:
<div class="container">
<section class="demo">
<ul>
<li></li>
<li></li>
<li></li>
</ul>
</section>
<section class="students"><ul></ul></section>
<section class="buttonList">
<ul>
<li><button type="button">随机选一个</button></li>
<li><button type="button">随机选两个</button></li>
<li><button type="button">随机选三个</button></li>
</ul>
</section>
</div>css:
<style type="text/css">
* {
margin: 0;
padding: 0;
}
ul {
list-style: none;
}
body {
width: 100%;
height: 100%;
background: url("images/bg.jpg") no-repeat;
background-size: cover;
}
button {
border: none;
background-color: transparent;
color: #fff;
font-size: 20px;
}
.container {
width: 1200px;
height: 700px;
margin: 10px auto;
}
.container .demo, .container .buttonList {
width: inherit;
height: 25%;
}
.container .students {
width: inherit;
height: 50%;
}
.container .students li {
margin-right: 50px;
margin-bottom: 30px;
text-align: center;
border-radius: 10px;
font-size: 20px;
font-weight: bold;
}
.container .students li:nth-child(5n) {
margin-right: 0;
}
.container .buttonList li button {
float: left;
width: 200px;
height: 60px;
background-color: #4caf5085;
margin-right: 150px;
text-align: center;
line-height: 60px;
border-radius: 10px;
margin-top: 50px;
font-weight: bold;
}
.container .buttonList li button:hover {
background-color: #4caf50;
}
.container .buttonList li:nth-child(1) {
margin-left: 150px;
}
.container .demo li {
width: 200px;
height: 150px;
background-color: #4caf5085;
float: left;
margin-right: 150px;
border-radius: 50%;
margin-top: 10px;
line-height: 150px;
font-weight: bold;
color: #fff;
font-size: 60px;
text-align: center;
}
.container .demo li:first-child {
margin-left: 150px;
}
</style>javascript:
<script type="text/javascript">
var stuArray = ["小方", "小田", "小明", "小红", "小吕", "小于", "小美", "小绿", "李华", "小李", "小胡",
"小夏", "小徐", "小小", "小吴", "小陈", "小狗", "小许", "小熊", "小新"];
var stuList = document.querySelector(".students").querySelector("ul");
var buttonList = document.querySelectorAll("button");
var demoList = document.querySelector(".demo").querySelectorAll("li");
for (var i = 0; i < stuArray.length; i++) {
var li = document.createElement("li");
stuList.appendChild(li);
li.innerHTML = stuArray[i];
li.style.cssFloat = "left";
li.style.width = 200 + "px";
li.style.height = 60 + "px";
li.style.backgroundColor = "#4caf5085";
li.style.color = "#fff";
li.style.lineHeight = 60 + "px";
}
var stuArrayList = stuList.querySelectorAll("li");
function chooseOne () {
for (var i = 0; i < stuArrayList.length; i++) {
stuArrayList[i].style.background = "#4caf5085";
}
for (var i = 0; i < demoList.length; i++) {
demoList[i].innerHTML = "";
}
var interId = setInterval(function () {
var x = Math.floor(Math.random() * stuArray.length);
stuArrayList[x].style.backgroundColor = "green";
demoList[1].innerHTML = stuArrayList[x].innerHTML;
var timeId = setTimeout(function () {
stuArrayList[x].style.backgroundColor = "#4caf5085";
}, 100);
var y = Math.floor(Math.random() * stuArray.length);
if (y == x) {
clearTimeout(timeId);
clearInterval(interId);
stuArrayList[y].style.backgroundColor = "green";
}
}, 100);
}
function chooseTwo () {
for (var i = 0; i < stuArrayList.length; i++) {
stuArrayList[i].style.background = "#4caf5085";
}
for (var i = 0; i < demoList.length; i++) {
demoList[i].innerHTML = "";
}
var interId = setInterval(function () {
do {
var x1 = Math.floor(Math.random() * stuArray.length);
var x2 = Math.floor(Math.random() * stuArray.length);
} while (x1 == x2);
stuArrayList[x1].style.backgroundColor = "green";
stuArrayList[x2].style.backgroundColor = "green";
demoList[0].innerHTML = stuArrayList[x1].innerHTML;
demoList[2].innerHTML = stuArrayList[x2].innerHTML;
var timeId = setTimeout(function () {
stuArrayList[x1].style.backgroundColor = "#4caf5085";
stuArrayList[x2].style.backgroundColor = "#4caf5085";
}, 100);
var y1 = Math.floor(Math.random() * stuArray.length);
var y2 = Math.floor(Math.random() * stuArray.length);
if ((y1 == x1 && y2 == x2) || (y1 == x2 && y2 == x1)) {
clearTimeout(timeId);
clearInterval(interId);
stuArrayList[x1].style.backgroundColor = "green";
stuArrayList[x2].style.backgroundColor = "green";
}
}, 100);
}
function chooseThree () {
for (var i = 0; i < stuArrayList.length; i++) {
stuArrayList[i].style.background = "#4caf5085";
}
for (var i = 0; i < demoList.length; i++) {
demoList[i].innerHTML = "";
}
var interId = setInterval(function () {
do {
var x1 = Math.floor(Math.random() * stuArray.length);
var x2 = Math.floor(Math.random() * stuArray.length);
var x3 = Math.floor(Math.random() * stuArray.length);
} while (x1 == x2 || x2 == x3 || x1 == x3);
stuArrayList[x1].style.backgroundColor = "green";
stuArrayList[x2].style.backgroundColor = "green";
stuArrayList[x3].style.backgroundColor = "green";
demoList[0].innerHTML = stuArrayList[x1].innerHTML;
demoList[1].innerHTML = stuArrayList[x2].innerHTML;
demoList[2].innerHTML = stuArrayList[x3].innerHTML;
var timeId = setTimeout(function () {
stuArrayList[x1].style.backgroundColor = "#4caf5085";
stuArrayList[x2].style.backgroundColor = "#4caf5085";
stuArrayList[x3].style.backgroundColor = "#4caf5085";
}, 100);
var y1 = Math.floor(Math.random() * stuArray.length);
var y2 = Math.floor(Math.random() * stuArray.length);
var y3 = Math.floor(Math.random() * stuArray.length);
if ((x1 == y1 && x2 == y2) || (x1 == y2 && x2 == y1)) {
clearTimeout(timeId);
clearInterval(interId);
stuArrayList[x1].style.backgroundColor = "green";
stuArrayList[x2].style.backgroundColor = "green";
stuArrayList[x3].style.backgroundColor = "green";
}
}, 100);
}
buttonList[0].addEventListener("click", function () {chooseOne()}, false);
buttonList[1].addEventListener("click", function () {chooseTwo()}, false);
buttonList[2].addEventListener("click", function () {chooseThree()}, false);原文地址：https://www.cnblogs.com/duxiu-fang/p/10795526.html
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