javascript - 如何使用 javascript 进行日计时器？

Question

我需要带日期的计时器。我想每天自动更改 HTML 表格中的行。

例如；如果是 11 日、12 日或 25 日，二月 08 点，则用“Hello!”更改行。 .

function time() {

  var xdate = new Date();
  var $second = xdate.getSeconds();
  var $minutes = xdate.getMinutes();
  var $hours = xdate.getHours();
  var $day = xdate.getDay();
  var $date = xdate.getDate();
  var $month = xdate.getMonth();
  var $year = xdate.getFullYear();

  console.log($date + "/" + $month + "---" + $hours + ":" + $minutes);
  setTimeout("time()", 1000);

  var x = document.getElementById("help1");

  if ($date == (11 || 12 || 25) && $month === 1 && $hours == 08) {
    document.getElementById("help1").innerHTML = "Hello"
  }
}
time();

<span id="help1">Hi</span>

Answer 1

你的意思可能是

const pad = num => ("0"+num).slice(-2);
function time() {

  var xdate = new Date();
  var hours = xdate.getHours();
  var minutes = xdate.getMinutes();
  var seconds = xdate.getSeconds();
  var date = xdate.getDate();
  var month = xdate.getMonth()+1; // months start at 0
  var year = xdate.getFullYear();

  x.innerHTML = date + "/" + pad(month) + "---" + pad(hours)+":"+pad(minutes)+":"+pad(seconds);
  
  // day 11 or 12 or 25 and month February and hour 8 
  
  if ((date === 11 || date === 12 || date === 25) && month === 2 && hours === 8) {
    x.innerHTML = "Hello"
    // clearInterval(tId); // this will stop the timer
  }
}
var x, tId;
window.addEventListener("load",function() {
  x = document.getElementById("help1");
  tId = setInterval(time,1000);
});

<span id="help1"></span>