Can one bypass the Oracle login screen?

The first thing that the user sees when using runform is the Oracle logon prompt asking them for their username, password, and database to connect to. You can bypass this screen or customise it by displaying your own logon screen. Eg:
ON-LOGIN
declare
uname varchar2(10);
pass varchar2(10);
begin
uname := 'username';
pass :='password';
logon(uname, pass||'@connect_database');
end;