CountDown timer for an auction

Hello,
I would like if someone can help me with an script or to guide me, for an countdown timer. I have an auction site and already a end date, but what i don't know is how to do to show me how many days hours and minutes.
I read several posts here, but none of them seems to work. It doesn't show nothing
this is it what i have, on my page, and it is showing the end date, but how do i do, to show a countdown  
 
This is .cs
stoptime.Text = dr["***"].ToString();

.aspx
<asp:Label id="stoptime" runat="server" Font-Bold="true" ForeColor="#0066FF" Font-Size="Small"></asp:Label>
 
Please can someone hellp me
Regards, 
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