Using Outlook 2003, I can't find help on how to validate fields in a form
based on default contact form by using the functions/formulae provided such
as "InStr( start , string1 , string2 , compare ) ", "Choose( index , expr )",
"Switch( expr1 , expr1 , expr2 , expr2 )" etc.
Where is an explanation of the syntax of these functions please?

For example, I want to validate whether a field contains any one of these
values: s, r, sr, rs or blank. How do I do this please?