attraction plate 3 such that when the door panel 7 is opened the attraction of the second magnetic attraction plate 6 exerted to the first magnetic attraction plate 3 drives the first magnetic attraction plate 3 and the limiting frame plate 2 to turn and move upward and the limiting slot 21 of the limiting frame plate 2 is framed around the corners 71 and the periphery of the door panel 7 or extended cross an outer side of the bottom of the door panel 7 so as to limit the door panel 7 at an opening position in the aforementioned method this embodiment is the same as the previous one in addition to the limiting frame plate 2 having the limiting slot 21 and the first magnetic attraction plate 3 this embodiment further comprises a fixed plate 1 and a link plate 4 and the linkage among the mutually pivoted fixed plate 1 limiting frame plate 2 first magnetic attraction plate 3 and link plate 4 forms a four link rod assembly when the first magnetic attraction plate 3 is magnetically attracted by the second magnetic attraction plate 6 the limiting frame plate 2 and the link plate 4 are driven to sway upward simultaneously so that the first magnetic attraction plate 3 is still parallel to the floor and the bottom of the door panel 7 during the moving process and the first magnetic attraction.