function isEmail(email)

	''' Validate email address '''
	Dim error, length, ValidationString, currentchar, i
	error = false

		''' case no @ or no dot'''
		if not (instr(email,"@") > 0) or not (instr(email,".") > 0) then
			
				error = true
		
		''' case no dot "." after strudel '''
		elseif not instrrev(email,".") > instr(email,"@") then
		
				error = true
		
		''' case @. '''
		elseif instr(email,"@.") then
		
				error = true
		
		''' case double @ '''	
		elseif instr(instr(email,"@") + 1,email,"@") > 0 then	
		
				error = true
				
		''' case start with @  '''
		elseif left(email,1) = "@" then
		
				error = true
				
		''' case ends with .  '''
		elseif right(email,1) = "." then
		
				error = true				
		
		''' case none valide chatacters '''
		else

			ValidationString = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_@^.-"
			length = len(email)
			
			for i = 1 to length	
				currentchar = left(right(email,i),1)
				if not instr(ValidationString ,currentchar) > 0 then
					error = true
				 	exit for
				end if	
			next
				
		end if
		
		isEmail = not error

end function