<!doctype html>
<html lang="en">
<head>
 <meta charset="gb2312">
 <title>抽獎活動</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:"微軟雅黑";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","鍵鼠套裝","1000元超市購物卡","200元話費充值卡","謝謝參與","品牌耳機","港澳臺7日游","50元優(yōu)惠券"],//定義獎品池
  timer=null,
  count=0;
//加載時觸發(fā)
 window.onload=function(){
 var start = document.getElementById("start");
 var stop = document.getElementById("stop");
 
 start.onclick=startFun;//這個函數(shù)后面加括號，就直接調用了該函數(shù)，所以不要加
 stop.onclick=stopFun;
 
 //綁定鍵盤事件
 document.onkeyup=function(e){
  e = e || window.event;
 if(e.keyCode==13){
  if(count==0){
  startFun();
  count=1;
  }
 else{ 
  stopFun();
  count=0;
  }
 }
 }
 }
 
//點擊開始，標題欄開始輪動
 function startFun(){
 clearInterval(timer);//開始時，清除計時器，避免二次觸發(fā)
 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";
 
 }
 //點擊停止，標題欄停止輪動并輸出輪動結果
 function stopFun(){
 var start = document.getElementById("start"),
  txt = document.getElementById("txt"),
  title = document.getElementById("title");
 clearInterval(timer);//清除計時器，停止計時器
 start.style.background="#036";
 }
 
 
 </script>
<body>
 <div>
 <h2 id="title">開始抽獎！</h2>
 </div>
 <div class="btns">
 <span id="start">開始</span>
 <span id="stop">停止</span>
 </div>
 <div id="txt">支持回車鍵(Enter)開始/停止。</div>
</body>
</html>

效果圖：