A high strength T-joint for inflatable tubular is formed by forming a butt joint between the end of a first two tubular member and the side wall of a second tubular member. In an online game method, a product carrying an ID code assigned thereto and a number of image characters reflecting features of the product and correlated to the ID code are previously prepared, and a user can use the image characters as characters for the online game by inputting the ID code in the online game to register the image characters therein. This invention provides the power for the cellular phone set.