Child seat with restraining bar structure and method of operating the same

A child seat is provided with a restraining bar structure having an elastic or rigid link element that can be connected with a seating board of the child seat in a detachable manner. The restraining bar structure can be adjusted between different configurations, including an upright position engaged with a holder socket of the seating board for restraining a child, and a collapsed position out of engagement with the holder socket and lying horizontally on the seating board. The link element can be easily detached from the seating board for fully removing the restraining bar structure from the child seat. The child seat is simple to operate and enables the useage convenience to be improved.