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 

链接: https://fly63.com/article/detial/3150