How a login page works on php or html website?

Question

can any one help me and how can we link database to this

Answer 1

in each language this will be different, but you will do a select like, select * from users where login="userlogin" and pass="userpass", if this return something, the user can login, else he can't! where userlogin is the field for login in your html code, where userpass is the same but for password field.
PS: sorry for my bad english, i'm brazilian!