Thanks for the report. However, I'm not sure how to proceed here. If you're not getting the correct values, please report an issue to the jQuery project at https://github.com/jquery/jquery/issues with a test case using jQuery on JS Bin. Then, we'll be able to see what's the reason and maybe report an issue to Firefox.

Without a bug report with a test case I don't think there's much we can do.

Sorry, I posted it where you told me to post it in the previous response. Should i kill this and move it ?
And it is easy to show it does not work. Open firefox and go to https://www.w3schools.com/jquery/tryit.asp?filename=tryjquery_event_timestamp
The results in Android or Internet explorer are completely different.

I guess we can continue here for now until we settle up whether there's a jQuery issue or a docs one.

I see similar behavior in Chrome, Firefox, Safari & Edge. Only IE shows time from January 1, 1970.

According to the spec:

Returns the event’s timestamp as the number of milliseconds measured relative to the time origin.

The time origin link redirects to another spec that says:

• If the global object is a Window object, the time origin MUST be equal to:
  • the time when the browsing context is first created if there is no previous document;

which suggests our docs are incorrect as we document the legacy IE behavior.

We should update the documentation then.

MDN also documents it in this way: https://developer.mozilla.org/en-US/docs/Web/API/Event/timeStamp

This value is the number of milliseconds elapsed from the beginning of the current document's lifetime till the event was created.

Just FYI, I tested it on my android device, and it showed the time from 1970.
I have not tested it on an apple iPhone or tablet. none of our staff have them.

Here's info about when it changed in Chrome: https://googlechrome.github.io/samples/event-timestamp/

Since the standard have changed, we should perhaps just update the docs. We might try normalizing it for IE, though I'm not sure how easy that would be as we'd need a way to find the page load time.

Perhaps it's best to just update the docs that it's no longer time from 1970 but from the current document timeline.

The critical thing about event.timeStamp is that it should represent the time at which the original event occurred. In the meantime it might have been queued, for example if there was some other blocking JavaScript running. There is no way we can fill in the value accurately because by the time the event is delivered to jQuery some unknown amount of time has passed. If someone just wants to know the time their event handler saw the event they can save the current time in the jQuery handler.

We should probably just update the docs to say that event.timeStamp is whatever the current browser says it is. See also https://bugs.jquery.com/ticket/10755 .