I want to design like I can access second page only after successful login. Can anyone please help?

Hi, you are only implementing the front-end side (html, css, js, and other static assets). You would need to implement server side logic (aka, back-end).

You would need a database to store users and their passwords (MySQL, PostgreSQL, MongoDB, others), you would need a server language (NodeJS, PHP, Java, Python, others) to implement logic to handle HTTP requests, connect to DB and create users, check if passwords match, hash passwords before storing in the DB, etc.

If you don't want to implement the server side logic, I would recommend using Google Firebase Authentication, so you wouldn't need to worry about storing data, implementing auth, etc.

Firebase gives you some options to authentication, like email/password, phone numbers, social media (Facebook, Google, Twitter, Github).
 
You are looking for authenticating from the ]web api[/url]