How to I edit cdosys.asp in "classic ASP" to send e-mail? - asp-classic

Question

I have a site that is all static content except the "Contact" page. My hosting service has me on an IIS server, so they gave me generic cdosys.asp file. As you know if you've used a cdosys.asp, you point the form submit from the contact page at it, and the cdosys.asp shoots whatever the site visitor put in the form fields in an email to me, then relays the visitor to a "Thanks for writing" page.
Here's my glitch. The only server-side language I've learned is ColdFusion. No ASP. The cdosys file was simple enough to figure out that I changed a few text strings so it points to my mail server and then the thank-you page. But, my contact input form only requires one out of the three offered fields. Two are optional. But the cdosys is choking on that. It thinks all the fields are required. It only works if all three have content. I Googled all over trying to find an old ASP tutorial. Can some kindly ASP pro out there tell me how to edit the code below to allow two of my three form fields to have no content and still send me an email?
<%
For Field = 1 to Request.Form.Count - 3
FieldName = Replace(Request.Form.Key(Field),"_"," ")
FieldValue = Request.Form.Item(Field)
Body = Body & FieldName & ": " & FieldValue & VbCrLf
Next
'Dimension variables
Dim objCDOSYSCon
'Create the e-mail server object
Set objCDOSYSMail = Server.CreateObject("CDO.Message")
Set objCDOSYSCon = Server.CreateObject ("CDO.Configuration")
'Set and update fields properties
With objCDOSYSCon
'Outgoing SMTP server
.Fields("http://schemas.microsoft.com/cdo/configuration/smtpserver") = "mail.domain.com" 'was "SMTPSERVER"
.Fields("http://schemas.microsoft.com/cdo/configuration/smtpserverport") = 25 'CDO Port
.Fields("http://schemas.microsoft.com/cdo/configuration/sendusing") = 2 'Timeout
.Fields("http://schemas.microsoft.com/cdo/configuration/smtpconnectiontimeout") = 60
.Fields.Update
End With
'Update the CDOSYS Configuration
Set objCDOSYSMail.Configuration = objCDOSYSCon
'Set and update email properties
With objCDOSYSMail
'0=Low, 1=Normal, 2=High
.Fields("urn:schemas:httpmail:importance").Value = 1
'Who the e-mail is from
.From = Request.Form("email_address")
'Who the e-mail is sent to
.To = "myname#domain.com"
'Who the e-mail is CC'd to
.Cc = ""
'The subject of the e-mail
.Subject = Request.Form("email_subject")
'Set the e-mail body format (HTMLBody=HTML TextBody=Plain)
.TextBody = Body
.Fields.Update
'Send the e-mail
.Send
End With
'Close the server mail object
Set objCDOSYSMail = Nothing
Set objCDOSYSCon = Nothing
'Rederect after sending email
Response.Redirect Request.Form("redirect_to")
%>

Answer 1

Try like this:
For Field = 1 to Request.Form.Count - 3
FieldName = Replace(Request.Form.Key(Field),"_"," ")
FieldValue = Request.Form.Item(Field)
if isnull(fieldvalue) then fieldvalue = "(null)"
Body = Body & FieldName & ": " & FieldValue & VbCrLf
Next