JavaScript实现键盘控制的简易抽奖系统

window.onload = function(){
  var data = [
    "iphone 6s plus",
    "苹果Mac 笔记本",
    "美的洗衣机",
    "凌美钢笔",
    "谢谢参与",
    "索尼入耳式耳机",
    "雷柏机械键盘",
    "《javaScript高级程序设计》",
    "精美保温杯",
    "维尼小熊一只",
    "500元中国石化加油卡",
    "爱奇艺年费会员",
    "iPad mini",
    "32G U盘",
  ];
  var bStop = true;
  var timer = null;
  var btns = document.getElementById('btns').getElementsByTagName('span');
  var text = document.getElementById('text');

  btns[0].onclick = start;
  btns[1].onclick = stop;

  document.onkeyup = function(event){
    event = event||window.event;
    if(event.keyCode==13){
      if(bStop){
        start();
      }else {
        stop();
      }
    }
  }

  function start(){
    clearInterval(timer);
    timer = setInterval(function(){
      var r = Math.floor(Math.random()*data.length);
      text.innerHTML = data[r];
    },20);
    btns[0].style.background = '#666';
    bStop = false;
  }

  function stop(){
    clearInterval(timer);
    btns[0].style.background = 'blue';
      bStop = true;
    
  }
}

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>抽奖啦</title>
  <style>
    * {
      margin: 0;
      padding:0;
    }
    #container {
      width: 500px;
      height: 200px;
      margin: 100px auto;
      background: red;
      position: relative;
      padding-top: 20px;
    }
    #container p {
      position: absolute;
      bottom: 4px;
      left: 30px;
    }
    #btns {
      position: absolute;
      left: 118px;
      bottom: 30px;
    }
    #container h1 {
      color: #fff;
      text-align: center;
    }
    #btn-start,#btn-stop {
      width: 100px;
      height: 60px;
      background: blue;
      text-align: center;
      line-height: 60px;
      font-size: 20px;
      display: inline-block;
      color: #fff;
      margin-right: 60px;
      border-radius: 10px;
      cursor: pointer;
    }
  </style>
  <script src="index.js"></script>
</head>
<body>
  <div id="container">
    <h1 id="text">iphone 6s plus</h1>
    <p>小提示:您可以按下Enter键来控制开始暂停,祝您中大奖哟</p>
    <div id="btns">
      <span id="btn-start">开始</span>
      <span id="btn-stop">停止</span>
    </div>
  </div>
</body>
</html>