为什么在 javascript 中计算时差时会得到 +1 小时? [英] Why do I get +1 hour when calculating time difference in javascript?

问题描述

我试图创建一个非常简单的时差计算.只是结束时间 - 开始时间".不过我得到了 +1 小时.我怀疑这与我的时区有关，因为我是 GMT+1.

I trying to create a very simple time difference calculation. Just "endtime - starttime". I'm getting +1 hour though. I suspect it has with my timezone to do, since I'm GMT+1.

无论如何，这不应该影响差异，因为开始和结束时间都在同一时区.

Regardless, that should not affect the difference, since both start and end times are in the same timezone.

在此处检查我正在运行的示例代码:

Check my running example-code here:

http://jsfiddle.net/kaze72/Rm3f3/

$(document).ready(function() {
    var tid1 =  (new Date).getTime();

    $("#tid").click(function() {
        var nu = (new Date).getTime();
        var diff = new Date(nu - tid1);
        console.log(diff.getUTCHours() + ":" +
                diff.getUTCMinutes() + ":" +
               diff.getUTCSeconds());  
        console.log(diff.toLocaleTimeString());
    });
})

推荐答案

您必须了解 Date 对象代表什么以及它如何存储日期.基本上每个 Date 都是围绕自 1970 年以来的毫秒数(所谓的纪元时间)的薄包装.通过从另一个日期中减去一个日期，您不会得到日期:您只会得到两者之间的毫秒数.

You must understand what Date object represent and how it stores dates. Basically each Date is a thin wrapper around the number of milliseconds since 1970 (so called epoch time). By subtracting one date from another you don't get a date: you just get the number of milliseconds between the two.

话虽如此，这条线没有多大意义:

That being said this line doesn't have much sense:

var diff = new Date(nu - tid1);

你真正需要的是:

var diffMillis = nu - tid1;

...然后简单地提取秒、分钟等:

...and then simply extract seconds, minutes, etc.:

var seconds = Math.floor(diffMillis / 1000);
var secondsPart = seconds % 60;
var minutes = Math.floor(seconds / 60);
var minutesPart = minutes % 60;
var hoursPart = Math.floor(minutes / 60);
//...
console.log(hoursPart + ":" + minutesPart + ":" + secondsPart);  

工作小提琴.

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