How can I get seconds since epoch in Javascript?

Question

On Unix, I can run date \'+%s\' to get the amount of seconds since epoch. But I need to query that in a browser front-end, not back-end.

Is there a way

Answer 1

If you want only seconds as a whole number without the decimals representing milliseconds still attached, use this:

var seconds = Math.floor(new Date() / 1000);

Answer 2

You can create a Date object (which will have the current time in it) and then call getTime() to get the ms since epoch.

var ms = new Date().getTime();

If you want seconds, then divide it by 1000:

var sec = new Date().getTime() / 1000;

Answer 3

The most simple version:

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

Answer 4

The above solutions use instance properties. Another way is to use the class property Date.now:

var time_in_millis = Date.now();
var time_in_seconds = time_in_millis / 1000;

If you want time_in_seconds to be an integer you have 2 options:

a. If you want to be consistent with C style truncation:

time_in_seconds_int = time_in_seconds >= 0 ?
                      Math.floor(time_in_seconds) : Math.ceil(time_in_seconds);

b. If you want to just have the mathematical definition of integer division to hold, just take the floor. (Python's integer division does this).

time_in_seconds_int = Math.floor(time_in_seconds);

Answer 5

In chrome you can open the console with F12 and test the following code:

var date = new Date().getTime()
console.debug('date: ' + date);

if (Date.now() < date)
    console.debug('ko');
else
    console.debug('ok');

https://www.eovao.com/en/a/javascript%20date/1/how-to-obtain-current-date-in-milliseconds-by-javascript-(epoch)

Answer 6

var seconds = new Date() / 1000;

Or, for a less hacky version:

var d = new Date();
var seconds = d.getTime() / 1000;

Don't forget to Math.floor() or Math.round() to round to nearest whole number or you might get a very odd decimal that you don't want:

var d = new Date();
var seconds = Math.round(d.getTime() / 1000);