How would i implement the following in html, with Jscript.

I have created a login form how do i make it so that when i post the form it stores the username and password values locally and when the user logs in he will have a specific instance of the homepage unique to him, and so all changes that he makes to the homepage need to be his as when another user logs in he needs to be able to do the same e.g. store his details locally and have a unique instance of the homepage.

If possible can you show me the code that you would use for this, I am using HTML, CSS, Jscript.