抽奖系统(慕课网题目)

要求实现功能:

1.点击左侧按键,开始抽奖,点击右侧按键,停止抽奖;

2.敲击回车键,开始抽奖,再次敲击回车键,停止抽奖;

3.开始抽奖后,左侧按钮变色;

html:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>抽奖</title>
    <link rel="stylesheet" href="style.css">
    <script src="eventUtil.js"></script>
    <script src="js.js"></script>
</head>
<body>
<div class="box">
    <div id="header">开始抽奖啦!</div>
    <div id="btn">
        <span id="start">开始</span>
        <span id="stop">结束</span>
    </div>
</div>
</body>
</html>

css:

body{
    margin: 0;
    padding: 0;
}
.box{
    width: 400px;
    height: 200px;
    border: 1px solid #0C4E7C;
    margin: 0 auto;
}
#header{
    color:darkred;
    font-size: 24px;
    text-align: center;
    width: 400px;
    height: 60px;
    line-height: 60px;
}
#btn{
    width: 200px;
    overflow: hidden;
    margin: 30px auto 0;
}
#btn span{
    cursor: pointer;
    border: 2px solid #a09a09;
    border-radius: 7px;
    margin-right: 10px;
    color: #000;
    display: inline-block;
    height: 40px;
    width: 80px;
    background-color: #f2ec55;
    line-height: 40px;
    text-align: center;
}

JavaScript:

js.js:
var date = ["谢谢参与", "谢谢参与", "谢谢参与", "50元话费", "ipad", "佳能相机", "苹果手机", "3DS", "switch", "1000元超市购物卡"];
var timer = null;
var flag = 0;


window.onload = function () {

    // var header = document.getElementById("header");优化前
    var start = document.getElementById("start");
    var stop = document.getElementById("stop");
//鼠标抽奖
    eventUtil.addHandler(start, "click", getStart);
    eventUtil.addHandler(stop, "click", getStop);
//键盘抽奖;
    document.onkeyup = function (event) {
        var e = event || window.event;
        //检测按键键值;
        // console.log(e.keyCode);
        if (e.keyCode === 13) {
            if (flag === 0) {
                getStart();
                flag = 1;
            } else {
                getStop();
                flag = 0;
            }
        }
    };

    function getStart() {
        clearInterval(timer);
        var header = document.getElementById("header");//优化后
        timer = setInterval(function () {
            //代码优化前
            //var x = parseInt(Math.random()*10);
            var random = Math.floor(Math.random() * date.length);
            header.innerHTML = date[random];
        }, 50);
        start.style.backgroundColor = "#999";
        flag = 1;
    }

    function getStop() {
        clearInterval(timer);
        start.style.backgroundColor = "#f2ec55";
        flag = 0;
    }
};
eventUtil.js
var eventUtil = {
    getEvent:function (event) {
        return event?event:window.event;
    },
    getType: function (event) {
        return event.type;
    },
    getTarget:function (event) {
        return event.target||event.srcElement;
    },
    //阻止冒泡
    stopPropagation:function (event) {
        if(event.stopPropagation){
            event.stopPropagation();
        }else {
            event.cancelBubble=true;
        }
    },
    //阻止事件默认行为;
    preventDefault:function(event){
        if(event.preventDefault){
            event.preventDefault();
        }else {
            event.returnValue = false;
        }
    },
    //添加具柄;
    addHandler: function (element, type, Handler) {
        if (element.ç) {
            element.addEventListener(type, Handler, false);
        } else if (element.attachEvent) {
            element.attachEvent("on" + type, Handler);
        } else {
            element["on" + type] = Handler;
        }
    },
    //删除具柄;
    removeHandler: function (element, type, Handler) {
        if (element.removeEventListener) {
            element.removeEventListener(type, Handler, false);
        } else if (element.detachEvent) {
            element.detachEvent("on" + type, Handler);
        } else {
            element["on" + type] = null;
        }
    }
};
原文地址:https://www.cnblogs.com/sunxirui00/p/7512570.html