function EmailField(fTestString) 
	TheAt = Instr(2, fTestString, "@")
	if TheAt = 0 then 
		EmailField = 0
	else
		TheDot = Instr(cLng(TheAt) + 2, fTestString, ".")
		if TheDot = 0 then
			EmailField = 0
		else
			if cLng(TheDot) + 1 > Len(fTestString) then
				EmailField = 0
			else
				EmailField = -1
			end if
		end if
	end if
end function 

function EmailField(fTestString)
	' checks for a vaild email
	' returns 0 for invalid addresses
	' returns -1 for valid addresses
	dim atCnt
	EmailField = -1

	' chk length
	' a@b.c should be the shortest an
	' address could be
	if len(fTestString) < 5  then
		EmailField = 0

	' chk format
	' has at least one "@"
	elseif instr(fTestString,"@") = 0 then
		EmailField = 0

	' has at least one "."
	elseif instr(fTestString,".") = 0 then
		EmailField = 0

	' has no more than 6 chars after last "."
	elseif len(fTestString) - instrrev(fTestString,".") > 6 then
		EmailField = 0

	' has no "_" after the "@"
	elseif instr(fTestString,"_") <> 0 and instrrev(fTestString,"_") > instrrev(fTestString,"@")  then
		EmailField = 0

	' has only one "@"
	else
		atCnt = 0
		for i = 1 to len(fTestString)
			if  mid(fTestString,i,1) = "@" then
				atCnt = atCnt + 1
			end if
		next

		if atCnt > 1 then
			EmailField = 0
		end if

		' chk each char for validity
		for i = 1 to len(fTestString)
			if not isnumeric(mid(fTestString,i,1)) and _
			(lcase(mid(fTestString,i,1)) < "a" or _
			lcase(mid(fTestString,i,1)) > "z") and _
			mid(fTestString,i,1) <> "_" and _
			mid(fTestString,i,1) <> "." and _
			mid(fTestString,i,1) <> "@" and _
			mid(fTestString,i,1) <> "-" then
				EmailField = 0
			end if
		next
	end if
end function

	' has no more than 3 chars after last "."
	elseif len(fTestString) - instrrev(fTestString,".") > 3 then
		EmailField = 0