Expandable bathroom door

A retractable bathroom door, comprising:

• a fixed frame, a mobile frame, a first parallel pull string and a foldable portion, wherein the fixed frame comprises an upper frame portion and a lower frame portion both of which are parallel to a horizontal surface, and a left frame portion and a right frame portion both of which are perpendicular to the horizontal surface;
• the upper frame portion, the lower frame portion, the left frame portion and the right frame portion are connected with each other end to end in sequence;
• the mobile frame is perpendicular to the upper frame portion and horizontally moves in a frame range of the fixed frame;
• a frame portion at one side of the mobile frame has a first hollow structure;
• a first upper pulley and a first lower pulley are respectively disposed at a top end and a bottom end of the first hollow structure;
• the first parallel pull string has two ends which are connected and wound around the first upper pulley and the first lower pulley in a crossover manner;
• an upper rail is disposed on the upper frame portion, a lower rail is disposed on the lower frame portion;
• an upper rack is disposed on the upper rail, a lower rack is disposed on the lower rail;
• the top end and the bottom end of the first hollow structure has a first upper opening and a first lower opening, respectively;
• one end of the upper rack enters the first hollow structure from the first upper opening and is connected with the first parallel pull string;
• one end of the lower rack enter the first hollow structure from the first lower opening and is connected with the first parallel pull string;
• a length of the upper rack disposed on the upper rail is as same as a length of the lower rack disposed on the lower rail;
• the foldable portion is disposed between two mobile frame portions of the mobile frame.