httpservice is not working properly

Question

i want to display server time on the browser.

created a httpservice that will obtain server time over http in json format

obtained the difference between server time and client time in seconds (date.time)

i update the clock every 1 sec. display the client time + the difference

But the problem here is

it runs in the initial load. when i load in multiple computers at the same time, the times are not in sync. there's a difference of one minute. in some computers, when i refresh the time goes back to the time obtained during the first request. Is there any other better method?