<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>抽奖活动</title>
<style>
* {
margin: 0;
padding: 0;
}
#title {
color: red;
text-align: center;
margin: 0 auto;
width: 240px;
height: 70px;
padding-top: 10px;
background: opacity(0);
}
.btns {
width: 190px;
height: 30px;
margin: 0px auto;
}
.btns span {
display: block;
float: left;
width: 80px;
height: 28px;
text-align: center;
background: #036;
color: #fff;
cursor: pointer;
border: 1px solid #eee;
border-radius: 8px;
font-family: "微软雅黑";
font-size: 14px;
line-height: 28px;
margin-right: 10px;
}
#txt {
font-size: 14px;
color: #ccc999;
text-align: center;
margin: 0 auto;
width: 190px;
height: 50px;
padding-top: 10px;
}
</style>
<script>
var mytype = ["iPhone6s", "iPad Air2", "DELL外星人", "键鼠套装", "1000元超市购物卡", "200元话费充值卡", "谢谢参与", "品牌耳机", "港澳台7日游", "50元优惠券"], //定义奖品池
timer = null,
count = 0;
//加载时触发
window.onload = function() {
var start = document.getElementById("start");
var stop = document.getElementById("stop");
start.onclick = startFun; //这个函数后面加括号，就直接调用了该函数，所以不要加
stop.onclick = stopFun;
//绑定键盘事件
document.onkeyup = function(e) {
e = e || window.event;
if(e.keyCode == 13) {
if(count == 0) {
startFun();
count = 1;
} else {
stopFun();
count = 0;
}
}
}
}
//点击开始，标题栏开始轮动
function startFun() {
clearInterval(timer); //开始时，清除计时器，避免二次触发
var title = document.getElementById("title");
var start = document.getElementById("start");
timer = setInterval(function() {
var num = Math.floor(Math.random() * mytype.length);
title.innerHTML = mytype[num];
}, 50);
start.style.background = "#ccc";
}
//点击停止，标题栏停止轮动并输出轮动结果
function stopFun() {
var start = document.getElementById("start"),
txt = document.getElementById("txt"),
title = document.getElementById("title");
clearInterval(timer); //清除计时器，停止计时器
start.style.background = "#036";
}
</script>
<body>
<div>
<h2 id="title">开始抽奖！</h2>
</div>
<div class="btns">
<span id="start">开始</span>
<span id="stop">停止</span>
</div>
<div id="txt">支持回车键(Enter)开始/停止。</div>
</body>
</html>