Make a Javascript countdown that resets itself automatically

Understanding
Substepr used to use a javascript timer that had to be reset manually via the control panel for the server. It would have wasted less time if the timer were able to reset itself automatically. The following is the code that Substepr used:

 TargetDate = "6/3/2012 8:00 PM"; BackColor = "white"; ForeColor = "navy"; CountActive = true; CountStepper = -1; LeadingZero = true; DisplayFormat = "%%D%% Days %%H%% Hours %%M%% Minutes %%S%% Seconds"; FinishMessage = "We have a new winner. See our Main Page."; 

This timer used to be seen running in the top left corner of any Substepr page.

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