Driver code
var head = newNode ( 1 ) ; head . next = newNode ( 2 ) ; head . next . next = newNode ( 3 ) ; head . next . next . next = newNode ( 4 ) ; head . next . next . next . next = newNode ( 5 ) ; head . next . next . next . next . next = newNode ( 4 ) ; head . next . next . next . next . next . next = newNode ( 4 ) ; document . write ( " " ) ; display ( head ) ; deleteLast ( head , 4 ) ; document . write ( " " ) ; display ( head ) ;