from tkinter import *

def reg():
    s1 = e1.get()
    s2 = e2.get()
    t1 = len(s1)
    t2 = len(s2)
    if s1 == "111" and s2 == "222":
        c["text"] = "登录成功"
    else:
        c["text"] = "登录失败"
        e1.delete(0, t1)
        e2.delete(0, t2)

root = Tk()
l1 = Label(root, text = "用户名: ")
l1.grid(row = 0, column = 0, sticky = W)
e1 = Entry(root)
e1.grid(row = 0, column = 1, sticky = E)

l2 = Label(root, text = "密码: ")
l2.grid(row = 1, column = 0, sticky = W)
e2 = Entry(root)
e2["show"] = '*'
e2.grid(row = 1, column = 1, sticky = E)

b = Button(root, text = "登录", command = reg)
b.grid(row = 2, column = 1, sticky = E)

c = Label(root, text = "")
c.grid(row = 3)

root.resizable(width=False, height=False)
root.mainloop()
