Improved secure login form

First you should always store a (salted) hash of the password, not the password itself. You then compare the hash of the posted password to the stored hash. That way if your site goes get hacked the attacker cannot use the login credentials of your users on other sites for example.
Second, you should validate your users input before using it.

But seriously, I doubt your skill level is at the level it should be in order to create a secured login feature. I would advise you to implement an existing auth library. I use Ion auth in all my projects.