function randomNum(){var r = Math.floor(Math.random() * 8); var str = "崔涛|徐敏学|陈阳|殷佳美|崔涛|徐敏学|陈阳|殷佳美" var arr = str.split('|'); document.getElementById('in').value = arr[r];}var time;var a;var flag=0;document.getElementById('start') .addEventListener('click',function(){    if(flag==0) time = setInterval(randomNum,100); flag=1; });document.getElementById('end') .addEventListener('click',function(){ clearInterval(time); flag=0;});window.onkeydown=function(e){ console.log(e.keyCode); console.log(flag); if(e.keyCode==13&&flag==0) { time = setInterval(randomNum,100); flag=1; } else if(e.keyCode==13&&flag==1) { clearTimeout(time); flag=0; }}