javascript实现仿微信抢红包
demo效果查看：http://www.w3cfuns.com/notes/14456/53bf08daf9b76230b39519fb399a006a
实现代码如下：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>仿微信抢红包</title> <style> html,body,div{margin:0;padding:0;} body{background:#EAEAEA;font:16px/1.8 "微软雅黑";padding-bottom:20px} input{margin:0;display:inline-block;border:1px solid #ddd;padding:4px 2px;font-size:16px;font-family:"微软雅黑";margin-right: 5px;} input:focus{border-color:#3C9BD1;outline:none;} .wrap,.list { margin: 50px auto; width: 300px;} .title{ font-size: 42px; color: #464646;text-align: center;} .line{height:40px;line-height:40px;text-align: center;} .btn{display:block;background:#3C9BD1;color:#fff;line-height: 40px;height:40px;text-align: center;width:200px;margin:0 auto;margin-top:50px;text-decoration: none;transition:all .3s linear;border-radius: 2px;} .btn:hover{opacity:.9;} .list{width:500px;border:1px solid #DBDBDB;padding:10px;BACKGROUND:#F5F5F5;text-align: center;} .list p span {color: red; padding: 0 8px;} .list p:empty{background: #000000;} .list:empty{display: none;} .link{position:fixed;height:20px;font-size: 12px;color:#999;text-align: center;width: 100%;bottom:0;line-height:20px;margin:0;padding:0; background: #EAEAEA;padding:5px 0;} .link a{font-size:12px;color:#999;} </style> </head> <body> <h1 class="title">javascript实现仿微信抢红包</h1> <div class="wrap"> <div class="line">红包个数：<input type="text" name="packetNumber" value="5" onkeyup="this.value=this.value.replace(/\D/g,'')" onafterpaste="this.value=this.value.replace(/\D/g,'')" maxlength="10">个</div> <div class="line">总 金 额：<input type="text" name="money" value="5" onkeyup="if(isNaN(value))execCommand('undo')" onafterpaste="if(isNaN(value))execCommand('undo')" maxlength="10">元</div> <div class="line"><a class="btn" href="javascript:;">发红包</a></div> </div> <div class="list"></div> <p class="link">参考<a target="_blank" href="https://www.zybuluo.com/yulin718/note/93148">《微信红包的架构设计简介》</a>文章</p> <script> "use strict"; var _createClass = function() { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function(Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; } ; }(); function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } } var MoneyPacket = function() { function MoneyPacket(packNumber, money) { _classCallCheck(this, MoneyPacket); this.min = 0.01; this.flag = true; this.packNumber = packNumber; this.money = money; if (!this.checkPackage()) { this.flag = false; return { "flag": this.flag }; } } _createClass(MoneyPacket, [{ key: "checkPackage", value: function checkPackage() { if (this.packNumber == 0) { alert("至少需要设置1个红包"); return false; } if (this.money <= 0) { alert("红包总金额不能小于0"); return false; } if (this.packNumber * this.min > this.money) { alert("单个红包金额不可低于0.01元"); return false; } return true; } }]); return MoneyPacket; }(); var getRandomMoney = function getRandomMoney(packet) { if (packet.packNumber == 0) { return; } if (packet.packNumber == 1) { var _lastMoney = Math.round(packet.money * 100) / 100; packet.packNumber--; packet.money = 0; return _lastMoney; } var min = 0.01 , max = packet.money / packet.packNumber * 2 , money = Math.random() * max; money = money < min ? min : money; money = Math.floor(money * 100) / 100; packet.packNumber--; packet.money = Math.round((packet.money - money) * 100) / 100; return money; } ; (function() { var oBtn = document.querySelector(".btn"); var oList = document.querySelector(".list"); oBtn.onclick = function() { var packetNumber = +document.querySelector("input[name=packetNumber]").value; var money = +document.querySelector("input[name=money]").value; var str = ""; var packet = new MoneyPacket(packetNumber,money) , num = packet.flag && packet.packNumber || 0; console.log("========================================================================"); for (var i = 0; i < num; i++) { var _pack = getRandomMoney(packet); str += "<p>第<span>" + i + "</span>个红包:: <span>" + _pack.toFixed(2) + "</span>元  ==剩余红包:: <span>" + packet.money.toFixed(2) + "</span> 元<p>"; console.log("第", i, "个红包::", _pack.toFixed(2), "元 ==剩余红包::", packet.money.toFixed(2), "元"); } str !== "" && (oList.innerHTML = str); } ; })(); </script> </body> </html>