ELSEIFNB          ELSE With IFNB                                    Directive

  ELSEIFNB <argument>

     This directive is the same as an ELSE followed by an IFNB. (IFNB is
     satified if argument is not blank.) It is used to start a nested
     conditional block. For example:

                        IF NUMBER EQ 5
                           add ax,3
                        ELSEIFNB NAME
                           add bx,2
                        ELSE
                           add cx,1
                        ENDIF

       Notes:     See ELSEIF and IFNB for more information.