I don't understand what you are saying about assigning
value to the same label the script is attached to?

This is what my HTML looks like.

<form id="Form1" method="post" runat="server">
<asp:label id="Lbl_TimeCounter" style="Z-INDEX:
101; LEFT: 8px; POSITION: absolute; TOP: 8px"
runat="server"></asp:label>
</form>