JS date verification regular with asp date formatting function_javascript skills

var pattern = /^((( (1[6-9]|[2-9]d)d{2})-(0?[13578]|1[02])-(0?[1-9]|[12]d|3[ 01]))|(((1[6-9]|[2-9]d)d{2})-(0?[13456789]|1[012])-(0?[1-9]| [12]d|30))|(((1[6-9]|[2-9]d)d{2})-0?2-(0?[1-9]|1d|2[0 -8]))|(((1[6-9]|[2-9]d)(0[48]|[2468][048]|[13579][26])|((16|[2468 ][048]|[3579][26])00))-0?2-29-))$/


if (!pattern.test(document.form1.pro_date.value) ) {
alert("The date format is incorrect, please re-enter!");
document.form1.pro_date.focus();
document.form1.pro_date.select();
return( false);

<%
' ================= ===========================
' Format time (display)
' Parameter: n_Flag
' 1: "yyyy-mm-dd hh:mm:ss"
' 2:"yyyy-mm-dd"
' 3:"hh:mm:ss"
' 4:"yyyy year mm month dd日"
' 5:"yyyymmdd"
' 6:"yyyymmddhhmmss"
' ========================== ==================
Function Format_Time(s_Time, n_Flag)
Dim y, m, d, h, mi, s
Format_Time = ""
If IsDate(s_Time) = False Then Exit Function
y = cstr(year(s_Time))
m = cstr(month(s_Time))
If len(m) = 1 Then m = "0" & ​​m
d = cstr(day(s_Time))
If len(d) = 1 Then d = "0" & ​​d
h = cstr(hour(s_Time))
If len(h) = 1 Then h = "0" & ​​h
mi = cstr(minute(s_Time))
If len(mi) = 1 Then mi = "0" & ​​mi
s = cstr(second(s_Time))
If len(s) = 1 Then s = "0" & ​​s
Select Case n_Flag
Case 1
' yyyy-mm-dd hh:mm:ss
Format_Time = y & "-" & m & "-" & d & " " & h & ":" & mi & ":" & s
Case 2
' yyyy-mm-dd
Format_Time = y & "-" & m & "-" & d
Case 3
' hh:mm:ss
Format_Time = h & ":" & mi & ":" & s
Case 4
' yyyy year mm dd day
Format_Time = y & "year" & m & "month" & d & "day"
Case 5
' yyyymmdd
Format_Time = y & m & d
case 6
'yyyymmddhhmmss
format_time= y & m & d & h & mi & s
End Select
End Function
%>