Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

function FormatStringforCGI(str: string): string;
 var
   i: integer;
 begin
   for i := 1 to Length(str) do
   begin
     if str[i] in ['a'..'z', 'A'..'Z', '0', '1'..'9'] then
       Result := Result + Str[i]
     else if Str[i] = ' ' then
       Result := Result + '+'
     else
       Result := Result + '%' + IntToHex(Byte(Str[i]), 2);
   end;
 end;