Negotiable Instruments Law
Section 7. When payable on demand.-An instrument is payable on demand-
(a) Where it is expressed to be payable on demand, or at sight, or on presentation; or
(b) In which no time for payment is expressed.
Where an instrument is issued, accepted, or indorsed when overdue, it is, as regards the person so issuing, accepting, or indorsing it, payable on demand.