用setTimeout模拟setInterval的功能

 var num=0;
  var max=10;
  function incrementNumber(){
    num++;
    if(num<max){
      setTimeout(incrementNumber,500);
      console.log(num);
    }
    else{
      console.log('Done');
    }
  }
  setTimeout(incrementNumber,500);

参考 https://www.cnblogs.com/lengyuehuahun/p/5650030.html