将十进制数转换为时间

function convertDecimalToTime(dec_num) {
  var hours = Math.floor(dec_num / 3600);
  var minutes = Math.floor((dec_num % 3600) / 60);
  var seconds = dec_num % 60;

  var timeString = formatTime(hours) + ":" + formatTime(minutes) + ":" + formatTime(seconds);
  
  return timeString;
}

function formatTime(time) {
  return time < 10 ? "0" + time : time;
}

var decimalNumber = 3665;
var time = convertDecimalToTime(decimalNumber);
console.log(time); // 输出：01:01:05