I originally thought that this system would be very complicated, but after analyzing each part clearly, I found that the skills required are not very high. However, when I organized all the functions and prepared them for encapsulation, I found that it was not easy to encapsulate the program because the coupling between the program and HTML was too high. Then I gradually separated the parts related to operating HTML in the program, first the simple separation, then the file list, then the file control, and finally some prompt programs. It took several attempts to encapsulate the entire structure.