<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
#wrap{
text-align: center;
width:500px;
margin: 100px auto;
position: relative;
}
#ul1{
width: 303px;
height: 303px;
margin: 50px auto;
padding:0;
border-top:1px solid black;
border-left: 1px solid black;
}
#ul1 li{
float: left;
border-right: 1px solid black;
border-bottom: 1px solid black;
list-style: none;
width: 100px;
height: 100px;
line-height: 100px;
text-align: center;
}
#tooltips{
width: 100%;
height: 100%;
background-color: rgba(0,0,0,0.5);
position: absolute;
top: 0;
z-index: 999;
display: none;
}
#info{
width: 400px;
height: 200px;
background-color: white;
margin: 150px auto;
}
#info .title{
width: 100%;
height: 40px;
background-color: #009f95;
line-height: 40px;
color: white;
padding-left: 20px;
box-sizing: border-box;
}
#info .btn button{
background-color: #009f95;
color: white;
outline: none;
font-size: 10px;
width:60px;
height: 30px;
margin-left: 300px;
}
#info .content {
height: 120px;
padding: 20px;
box-sizing: border-box;
}
</style>
</head>
<body>
<div id="wrap">
<button id="btn">開始抽獎</button>
<ul id="ul1">
<li>鼠標</li>
<li>1000萬</li>
<li>100優惠卷</li>
<li>很遺憾</li>
<li>鍵盤</li>
<li>iphoneX</li>
<li>很遺憾</li>
<li>迪拜10日游</li>
<li>很遺憾</li>
</ul>
</div>
<!-- 提示信息 -->
<div id="tooltips">
<div id="info">
<div class="title">信息</div>
<div class="content">恭喜你，中獎了</div>
<div class="btn">
<button id="confirm">確定</button>
</div>
</div>
</div>
<script type="text/javascript">
//思路： 1 實現紅色背景切換 2 當運動停止，彈出對話框--用js去修改tooltips的display 變為block
var oStart = document.getElementById("btn")
var aLi = document.getElementsByTagName("li")
//提示框
var oTooltips = document.getElementById("tooltips")
//確定按鈕
var oConfirm = document.getElementById("confirm")
//當前li的下標
var nowIndex = 0
// setInterval的id
var timer = null
oStart.onclick = function(){
//生成一個中獎數字
var randomInt = getRandomInt(0, 8)
console.log(randomInt)
//下面的代碼只是為了給用戶一個感覺：正在抽獎
timer = setInterval(function(){
for(var i = 0; i< aLi.length; i++){
aLi[i].style.backgroundColor = "white"
}
aLi[nowIndex].style.backgroundColor = "red"
nowIndex++
//randomInt表示中獎的數字，如果nowIndex和randomInt一樣，我們就認為當前的li是抽中的獎品
if(nowIndex === randomInt){
clearInterval(timer)
oTooltips.style.display = "block"
}
// nowIndex = nowIndex % aLi.length
nowIndex %= aLi.length
}, 500)
//思考一個問題：什么時候停止？當中獎的時候停止， 抽中的是誰？
//可以用隨機數生成一個具體中獎的數字 randomInt
}
//當點擊確定的時候，提示框消失
oConfirm.onclick = function(){
//讓tooltips消失
oTooltips.style.display = "none"
}
function getRandomInt(min, max){
return Math.floor(Math.random()*(max - min + 1) + min)
}
</script>
</body>
</html>
