你如何在 JavaScript 中获得时间戳? [英] How do you get a timestamp in JavaScript?

问题描述

类似于 Unix 的时间戳，它是代表当前时间和日期的单个数字.可以是数字或字符串.

解决方案

Short &时髦:

+ new Date()

像 plus 这样的一元运算符会触发 Date 对象中的 valueOf 方法，并返回时间戳(没有任何更改).

详情:

在几乎所有当前浏览器上，您都可以使用 Date.now() 以毫秒为单位获取UTC时间戳；一个值得注意的例外是 IE8 及更早版本(参见 兼容性表).

不过，您可以轻松地为此制作一个垫片:

if (!Date.now) {Date.now = function() { return new Date().getTime();}}

要以秒为单位获取时间戳，您可以使用:

Math.floor(Date.now()/1000)

或者你可以使用:

Date.now()/1000 |0

应该稍微快一点，但可读性也较差.
(也看到这个答案或this 以及对按位运算符的进一步解释).

我建议使用 Date.now()(带有兼容性垫片).它稍微好一点，因为它更短&不会创建新的 Date 对象.但是，如果你不想要一个垫片 &最大的兼容性，你可以使用旧的"以毫秒为单位获取时间戳的方法:

new Date().getTime()

然后您可以像这样将其转换为秒:

Math.round(new Date().getTime()/1000)

你也可以使用我们上面展示的 valueOf 方法:

new Date().valueOf()

时间戳(以毫秒为单位)

var timeStampInMs = window.performance &&window.performance.now &&window.performance.timing &&window.performance.timing.navigationStart ?window.performance.now() + window.performance.timing.navigationStart : Date.now();console.log(timeStampInMs, Date.now());

Something similar to Unix's timestamp, that is a single number that represents the current time and date. Either as a number or a string.

解决方案

Short & Snazzy:

+ new Date()

A unary operator like plus triggers the valueOf method in the Date object and it returns the timestamp (without any alteration).

Details:

On almost all current browsers you can use Date.now() to get the UTC timestamp in milliseconds; a notable exception to this is IE8 and earlier (see compatibility table).

You can easily make a shim for this, though:

if (!Date.now) {
    Date.now = function() { return new Date().getTime(); }
}

To get the timestamp in seconds, you can use:

Math.floor(Date.now() / 1000)

Or alternatively you could use:

Date.now() / 1000 | 0

Which should be slightly faster, but also less readable.
(also see this answer or this with further explaination to bitwise operators).

I would recommend using Date.now() (with compatibility shim). It's slightly better because it's shorter & doesn't create a new Date object. However, if you don't want a shim & maximum compatibility, you could use the "old" method to get the timestamp in milliseconds:

new Date().getTime()

Which you can then convert to seconds like this:

Math.round(new Date().getTime()/1000)

And you can also use the valueOf method which we showed above:

new Date().valueOf()

Timestamp in Milliseconds

var timeStampInMs = window.performance && window.performance.now && window.performance.timing && window.performance.timing.navigationStart ? window.performance.now() + window.performance.timing.navigationStart : Date.now();

console.log(timeStampInMs, Date.now());

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