I tried to control email address and reviewer's name with the following code but I received this error.

Microsoft VBScript runtime error '800a0005'

Invalid procedure call or argument: 'Mid'

Cant I compare Mid(REVIEWEREMAIL, InStr(1, REVIEWEREMAIL, "@", 1), 1) to "@"?

  If Len(REVIEWERNAME) < 2 Then
   with response
    .write "Error! Please fill in valid name. <br />"
   end with
  ElseIf Len(REVIEWEREMAIL) < 3 Then
   with response
    .write "Error! Please fill in valid email address. <br />"
   end with
  ElseIf Mid(REVIEWEREMAIL, InStr(1, REVIEWEREMAIL, "@", 1), 1) <> "@" Then
   with response
    .write "Error! Please fill in valid email address. <br />"
   end with
  Else

               insert...

End If