Applet程序，界面中包含两个按钮，一个按钮用于放大Applet上的一串字符串，一个按钮用于缩小；连续点击可不断放大或缩小-Applet process, the interface contains two buttons, one button for enlarge Applet on a bunch of string, a button for narrowing consecutive clicks can continually zoom in or out