Answer 1

localstorage is almost like cookies (main use cases: storing user infos accross sessions, as ui style preferences, form data, backup values to be retrieved if unexpected close of page occurs...)
Keys differences:
* localstorage is limited to client-side scope while cookies are send to server with almost all request
* localstorage provide more stockage space than cookies, but it still limited (around 5 to 10 Mo, depending on browsers, to be roughly divided by 2 as js string are utf-16 encoded/stored)
* localstorage is newest than cookies (Html5 specs vs quite always), so api is easiest to use, but potentially not supported (for today really old devices/browsers)
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