10 mins left trigger a popup alert

   <SCRIPT LANGUAGE="VBScript">
    <!--
    Dim intTimerID
    Dim hr
    Dim min
    Dim sec
   
   hr =<%=Session("Hr")%>'change hours
   min=<%=Session("Min")%>'change minutes
   sec=<%=Session("Sec")%>'change seconds
   
    Sub HandleTime
    if hr=0 and min=0 and sec=0 then
    endtime
    elseif min>=0 and sec>0 then
    sec=sec-1
    status= "Time Left: " & hr & " hr " & min & " min " & sec & " sec "
    intTimerID=setTimeOut("HandleTime",950, "VBScript")
    elseif min>0 and sec=0 then
    min=min-1
    sec=59
    status= "Time Left: " & hr & " hr " & min & " min " & sec & " sec "
    intTimerID=setTimeOut("HandleTime",950, "VBScript")
    elseif hr>=0 and min=0 then
    hr=hr-1
    min=59
    sec=59
    status= "Time Left: " & hr & " hr " & min & " min " & sec & " sec "
    intTimerID=setTimeOut("HandleTime",950, "VBScript")
    end if
   
    document.all.hours.value = Hr
    document.all.Mins.value = Min
    document.all.Secs.value = Sec
   
    End Sub
    Sub endtime
    cleartimeout intTimerID
    status = "Exam Time Ended"
    msgbox "Exam Time Is Up"
    Location.href = "end.asp"
   
   
   
    end sub
   
   
    status= "Time Left: " & hr & " hr " & min & " min " & sec & " sec "
    intTimerID=setTimeOut("HandleTime",950, "VBScript")
   
   
    -->
    </script>