Javascript Countdown Synchronize On Different Browsers

I'm sorry if this question is a bit tricky but I have no other way of asking it and I am an absolute noob in javascript world. I have this javascript counter that someone helped me

Solution 1:

JavaScript is always running on the client. One instance of the timer has no knowledge of any other instance running elsewhere.

To synchronize time between different browsers, you would need server-side scripts. Using expiration-time-stamps in a server-side script in conjunction with JavaScript timers should give you the synchronization you are looking for.

Solution 2:

Cookies are not transferred from browser to browser. They are stored in the web browser.