HELP: WORKING WITH MASTER PAGE

I put a timer in my Master Page.
I have three (3) labels, the three labels are for

You've been log in: [Hours]:[Minutes]:[Seconds]

I have different web pages, but whenever I click other page, the timer reset like:
You've been log in: [00]:[00]:[00]

What I want is once the user log in, the timer start
00:00:01

When I click other pages, I want the timer to just continue as it is and not to reset. :(