. 3 is a schematic diagram of the structure of the user's computer in the embodiment of the present invention; [0054]FIG. 4 is a schematic functional diagram of an information server in the embodiment of the present invention; [0055]FIG. 5 is a schematic structural diagram of the information server in the embodiment of the present invention; [0056]FIGS. 6a and 6 b are a flow diagram of the operati