在 JavaScript 中单调增加时间? [英] Monotonically increasing time in JavaScript?

问题描述

在 JavaScript 中获得单调增加时间的最佳方法是什么?我希望有类似 Java 的 System.nanoTime().

What’s the best way to get monotonically increasing time in JavaScript? I’m hoping for something like Java’s System.nanoTime().

Date() 显然不行，因为它受系统时间变化的影响.

Date() obviously won’t work, as it’s affected by system time changes.

换句话说，我想要的是一个 <= b，总是:

In other words, what I would like is for a <= b, always:

a = myIncreasingTime.getMilliseconds();
...
// some time later, maybe seconds, maybe days
b = myIncreasingTime.getMilliseconds();

充其量，即使在 Date() 中使用 UTC 函数时，它也会返回它认为是正确的时间，但如果有人将时间设置向后，则下一次调用 Date()可以返回较小的值.System.nanoTime() 不受此限制(至少在系统重新启动之前不会).

At best, even when using the UTC functions in Date(), it will return what it believes is the correct time, but if someone sets the time backward, the next call to Date() can return a lesser value. System.nanoTime() does not suffer from this limitation (at least not until the system is rebooted).

修改: [2012-02-26:无意影响原始问题，有赏金]

Modification: [2012-02-26: not intended to affect the original question, which has a bounty]

我对知道墙上时间"不感兴趣，我有兴趣知道过去时间的准确性，这是 Date() 不可能提供的.>

I am not interested knowing the "wall time", I’m interested in knowing elapsed time with some accuracy, which Date() cannot possibly provide.

推荐答案

您可以使用 window.performance.now() - 自 Firefox 15 和 window.performance.webkitNow() - Chrome 20]

You could use window.performance.now() - since Firefox 15, and window.performance.webkitNow() - Chrome 20]

var a = window.performance.now();
//...
var delay = window.performance.now() - a;

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