时间格式转换器 - 00::00:00

秒数转换成00:00:00格式

function toTwo(num){
       function changInt(num){
          return (num < 10) ? '0'+num : num;
       }
      return changInt(parseInt(num/3600))+":"+changInt(parseInt(num/60))+":"+ changInt(Math.round(num%60));
}