ASP data validation

<%

If Trim (Request ("action")) = "Add" Then

If Request.Form ("cn_name1") =empty or request. Form ("pwd") =empty or request. Form ("Pwd2") =empty or request. Form ("class") =empty Then

Response. Write ("<script language=javascript>" & Chr & "alert (' ERROR: Please enter the information in full!" with * entries must be filled in! '); "&" javascript: History.go ( -1) "&" </script> "

ElseIf Request.Form ("pwd") <> Request.Form ("Pwd2") Then

Response.Write ("<script language= ' JavaScript ' > Alert (' ERROR: the password does not match the confirmation password! '); Javascript:history.go ( -1) </script> ")

ElseIf Len (Request.Form ("cn_name1")) >16 Then

Response.Write ("<script language= ' JavaScript ' > Alert (' ERROR: User name is longer than 16 characters, 10 kanji '); Javascript:history.go ( -1) </script> ")

ElseIf Len (Request.Form ("cn_name1")) <4 Then

Response.Write ("<script language= ' JavaScript ' > Alert (' ERROR: User name length less than 4 characters, 2 kanji '); Javascript:history.go ( -1) </script> ")

ElseIf Len (Request.Form ("class")) <2 Then

Response.Write ("<script language= ' JavaScript ' > Alert (' Error: Class name less than 4 characters! '); Javascript:history.go ( -1) </script> ")

ElseIf Len (Request.Form ("pwd")) >20 or Len (Request.Form ("pwd")) <6 Then

Response.Write ("<script language= ' JavaScript ' > Alert (' ERROR: The length of the password you entered does not match! '); Javascript:history.go ( -1) </script> ")

End If

End If

%>

ASP data validation