具体代码：
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Math.random方法彩票随机数的生成-升级版</title> <style type="text/css"> *{ margin: 0; padding: 0; } .wrap{ width: 600px; height: 300px; background-color: #f8e2e2; margin: 0 auto; } .list{ width: 440px; /*border: 1px solid red;*/ margin: 0px auto; } .list li{ list-style: none; width: 30px; height: 30px; display: inline-block; border: 1px solid #fff; border-radius: 30px; line-height: 30px; text-align: center; margin: 15px auto 15px; /*background-color: #f8f8f8;*/ /*background-color: rgba(255,255,255,1);*/ } .wrap p{ text-align: center; } .wrap p button{ text-align: center; width: 100px; } #setBtn{ background-color: red; color: #fff; border: none; } .active{ background-color: red; color: #fff; } </style> </head> <body> <div> <ul> <li>01</li> <li>02</li> <li>03</li> <li>04</li> <li>05</li> <li>06</li> <li>07</li> <li>08</li> <li>09</li> <li>10</li> <li>11</li> <li>12</li> <li>13</li> <li>14</li> <li>15</li> <li>16</li> <li>17</li> <li>18</li> <li>19</li> <li>20</li> <li>21</li> <li>22</li> <li>23</li> <li>24</li> <li>25</li> <li>26</li> <li>27</li> <li>28</li> <li>29</li> <li>30</li> <li>31</li> <li>32</li> <li>33</li> </ul> <p> <button>随机红球</button> <button>清空</button> </p> </div> <script type="text/javascript"> var ballList = document.getElementById("wrap").getElementsByTagName("li"); var setBtn =document.getElementById("setBtn"); var clearBtn =document.getElementById("clearBtn"); //定义随机数组 function rnd(min, max) { return parseInt(Math.random()*(max - min + 1) + min); } function rndArray(min, max, length) { //先定义一个空数组 var arr = []; //生成一个长度为7的数组 while(arr.length < length) { //生成一个随机数 var rand = rnd(min, max); //判断生成的随机数rand是否在数组arr里,果然不在，就将这个随机数插入到数组里，如果在，执行下一次循环 if(arr.indexOf(rand) == -1) { arr.push(rand); } } arr.sort(function(a, b){return a - b;}) return arr; } function selectBall() { for(var j = 0; j < ballList.length; j++) { ballList[j].className = ""; } var arr = rndArray(1,33,7); // console.log(arr); for(var i = 0; i < arr.length; i++) { ballList[arr[i]-1].className = "active"; } } var timer = 0; setBtn.onclick = function() { clearTimeout(timer); timer = setInterval(selectBall,100); setTimeout(function() { clearTimeout(timer); },3000) // clearTimeout(timer); } clearBtn.onclick = function() { clearTimeout(timer); for(var j = 0; j < ballList.length; j++) { ballList[j].className = ""; } } </script> </body> </html>