为什么日期没有调整到 UTC 设置的时间？

Question

打印时钟的时间时，类似的代码可以工作并针对所选时区进行调整，但这不适用于打印日期。知道为什么吗？

它只显示 UTC 默认时间。

<script>
    function cetDT(){

var now = new Date();
var today = new Date(now.getUTCFullYear(), now.getUTCMonth(), now.getUTCDate(),  now.getUTCHours(), now.getUTCMinutes(), now.getUTCSeconds());

var day = today.getDate();
var month = today.getMonth();
var year = today.getFullYear();

var anHour = 1000 * 60 * 60;
today = new Date(today.getTime() - anHour * -2);

var hours = today.getHours();
var minutes = today.getMinutes();
var seconds = today.getSeconds();

if (hours >= 12){
meridiem = "";
}
else {
meridiem = "";
}


if (minutes<10){
minutes = "0" + minutes;
}
else {
minutes = minutes;
}

if (seconds<10){
seconds = "0" + seconds;
}
else {
seconds = seconds;
}

document.getElementById("cetDT").innerHTML = (day + '/' + (parseFloat (month) + 1) + '/' + year);

}

cetDT();
</script>

Answer 1

您正在使用 now.getUTCDate()、now.getUTCHours() 和类似名称，它们将获取 UTC 格式的当前日期和时间。

要获得本地等效项，您需要查找 now.getDate()、now.getHours() 等。请注意名称中缺少“UTC”。

请注意，即使您使用today = new Date(today.getTime() - anHour * -2)更新today 变量，today 也会更早地使用 UTC 时间进行初始化。因此，getTime() 将与 UTC 相关。

要解决这个问题，您只需换掉 UTC 时间：

function cetDT() {

  var now = new Date();
  var today = new Date(now.getFullYear(), now.getMonth(), now.getDate(), now.getHours(), now.getMinutes(), now.getSeconds());

  var day = today.getDate();
  var month = today.getMonth();
  var year = today.getFullYear();

  var anHour = 1000 * 60 * 60;
  today = new Date(today.getTime() - anHour * -2);

  var hours = today.getHours();
  var minutes = today.getMinutes();
  var seconds = today.getSeconds();

  if (hours >= 12) {
    meridiem = "";
  } else {
    meridiem = "";
  }


  if (minutes < 10) {
    minutes = "0" + minutes;
  } else {
    minutes = minutes;
  }

  if (seconds < 10) {
    seconds = "0" + seconds;
  } else {
    seconds = seconds;
  }

  document.getElementById("cetDT").innerHTML = (day + '/' + (parseFloat(month) + 1) + '/' + year);

}

cetDT();

请注意，还有一些完全冗余的代码，例如else { seconds = seconds; }。您可能希望考虑重构此代码；）

希望这会有所帮助！ :)