login page in asp.net
<p>hii i am new to web site development 
   there is a login page in my web site which is in ASP.net(C#.net) . After entering the username and password and user click on the Login button . The user name and password got check and it shows the message at the "the user name and password did'nt match" but i want this messageas a message box. Currently it is showing as a line on the left-top corner  of the page.. 
  if possible so please give the code</p>
