我如何把这个计时器变成一个每秒更新的函数？

function updateTimer() {
  var currentTime = new Date();
  var hours = currentTime.getHours();
  var minutes = currentTime.getMinutes();
  var seconds = currentTime.getSeconds();
  
  // 将时间格式化为两位数
  hours = (hours < 10 ? "0" : "") + hours;
  minutes = (minutes < 10 ? "0" : "") + minutes;
  seconds = (seconds < 10 ? "0" : "") + seconds;
  
  // 更新页面上的计时器显示
  var timerElement = document.getElementById("timer");
  timerElement.innerHTML = hours + ":" + minutes + ":" + seconds;
}

// 每秒调用一次updateTimer函数
setInterval(updateTimer, 1000);