Can someone please tell me how I can code a simple clock on my website. It doesn't need to be live, the time would just update when the page is refreshed.

I would need it in 3 timeszones. So at 5:45pm EST (New York time) it would display:

New York 17:45

London 22:45

Tokyo 7:45

I've seen clocks that detect your current time but I would need it in these specific time zones. Any help would be appreciated!