I want to make my website available offline even if the user clears the cache and cookies. Is is possible? Also I am dealing with database. Is is possible to handle databases offline?
A user could store a local copy of a single webpage using Chrome (right click save-as) and it will store all resources (images, css, js) required to fully load the page offline. Other browsers will have similar options.
You can use wget to mirror a whole website for offline browsing.
wget --mirror --convert-links --html-extension -p http://www.example.com/
of course neither of these options will handle database driven elements of your site/page.
If you want to mock a database or dynamic elements of a page offline then Google Gears is probably the closest to what you are looking for but I think it was deprecated by Google last year.