简单抽奖--测试键盘事件-原创手记-慕课网

1、index.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>简单抽奖系统-使用键盘事件</title>
    <link rel="stylesheet" type="text/css" href="css/style.css">
    <script type="text/javascript" src="js/script.js"></script>
</head>
<body>
    <div id="title" class="title">开始抽奖了!</div>
    <div class="btns">
        <span id="play">开 始</span>
        <span id="stop">停 止</span>
    </div>
</body>
</html>

2、css/style.css

*{
    margin:0;
    padding: 0;
}
.title{
    width:400px;
    height:70px;
    margin: 0 auto;
    text-align: center;
    padding-top: 30px;
    font-size: 24px;
    font-weight: bold;
    color: red;
}
.btns{
    width: 190px;
    height: 30px;
    margin: 0 auto;
}
.btns span{
    display: block;
    float:left;
    width:80px;
    height:27px;
    line-height: 27px;
    margin-right: 10px;
    text-align: center;
    background-color: blue;
    color: #fff;
    border: 1px solid red;
    border-radius: 7px;
    font-size:14px;
    font-family:"微软雅黑";
    cursor:pointer;
}

3、js/script.js

var data=['Phone5','Ipad','三星笔记本','佳能相机','惠普打印机','谢谢参与','50元充值卡','1000元超市购物券'],
    timer=null,//全局变量计时器
    flag=0;//全局变量Boolean值，用来判断回车键执行的逻辑，保证前后两次互斥
window.onload = function(){
    var oTitle = document.getElementById('title'),//中奖文本区域
        play = document.getElementById('play'),//开始按钮
        stop = document.getElementById('stop');//停止按钮
    play.onclick = playFun;
    stop.onclick = stopFun;
    document.onkeyup = function(event){
        event = event?event:window.event;
        if(event.keyCode==13){//回车键松开事件
            if(flag==0){
                playFun();
            }else{
                stopFun();
            }
        }
    }
    function playFun(){
        clearInterval(timer);//先清计时器，存在多次点击开始按钮，每点击一次生成一个新的计时器的情况，所以先清
        timer = setInterval(function(){
            var random = Math.floor(Math.random()*data.length);
            oTitle.innerHTML = data[random];
        },50);
        play.style.background = '#999';
        flag = 1;
    }
    function stopFun(){
        clearInterval(timer);
        play.style.background = 'blue';
        flag = 0;
    }
}