<script type="text/javascript">


    var t;

    function display() {

        if ((document.getElementById("<%=txtMin.ClientID%>").value == 0) && (document.getElementById("<%=txtSec.ClientID%>").value == 0)) {
                //if a popup window is used:
                setTimeout("self.close()", 1000);
                return;
            }
            else {
                document.getElementById("<%=txtSec.ClientID%>").value -= 1
                document.getElementById("<%=txtMin.ClientID%>").value = document.getElementById("<%=txtMin.ClientID%>").value
                document.getElementById("<%=txtSec.ClientID%>").value = document.getElementById("<%=txtSec.ClientID%>").value
                t = setTimeout("display()", 1000);
                if (document.getElementById("<%=txtSec.ClientID%>").value <= 0) {
                document.getElementById("<%=txtSec.ClientID%>").value = 60;
                document.getElementById("<%=txtMin.ClientID%>").value -= 1;
            }
        }
    }
    window.onload = display;