Countdown Timer with Cookie (Javascript?)

I am looking for a 60 minute countdown timer with cookie for a website. Essentially, here is what I need: - visitor arrive at website and countdown timer starts with minutes/seconds and cookie is set - if visitor refreshes browser or leaves the site the countdown continues - when the browser is refreshed or visitor returns to site - countdown does not restart (e.g. visitor arrives at site and countdown starts at 60 minutes - they leave the site for 10 mins when countdown timer is 53 mins - when they return the timer shows 43 mins) - at the end of the 60 minutes I can show some text - cookie is deleted - if visitor refreshes browser (or visits site again timer starts at 60 mins again with new cookie) and same cycle as above - I don't need any CSS for how the timer looks