Client-side persistence.
WHAT OPTIONS EXIST
Simple key and value storage, persisting indefinitely The same, cleared when the session ends A structured database in the browser Cookies
WHAT EACH SUITS
- Simple storage: small preferences and state
- Session storage: state for one browsing session
- The database: substantial structured data, offline work
- Cookies: data the server also needs
WHY COOKIES ARE DIFFERENT
They are sent with every request, which affects performance and has security implications.
WHAT TO NEVER STORE IN THE BROWSER
Secrets Sensitive personal data Anything you rely on being unmodified
WHY
It is visible and editable by the user, and readable by any script on the page.
WHAT TO ASSUME
That anything stored may be absent, cleared or full.
WHAT TO DO ABOUT THAT
Handle failure, and function without it.
WHAT TO BE AWARE OF
Storage limits, which vary Private browsing modes, where it may not persist Users clearing it
WHAT TO USE IT FOR
Conveniences, not for anything that must not be lost.
