点击开始抽奖，然后设定人员开始不定的改变，直到点击停止为止


代码如下

<div class="div">
    <h2>Who?</h2>
    <img src="cankao/start.jpg" width="100" id="q"> <img src="cankao/end.jpg" width="100" id="p">
</div>
</body>
<script>
        var usernames=["张三","李四","王五","赵六","孙琦","钱吧","八六"];
           var b=0;
           var c=0;
        function chou() {
            var a=document.querySelector("h2");
             c=setInterval(function () {
                if(b>usernames.length-1){
                    b=0;
                }
                    a.innerHTML = usernames[b];
                b++;
            },100);

        }
    function ding() {
        clearInterval(c);
    }
  document.querySelector("#q").onclick=chou;
  document.querySelector("#p").onclick=ding;
</script>