html - Local Storage vs Cookies

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I want to reduce load times on my
websites by moving all cookies into local storage since they seem to have the same
functionality. Are there any pros/cons (especially performance-wise) in using local
storage to replace cookie functionality except for the obvious compatibility
issues?

Answer

Cookies and local storage serve different
purposes. Cookies are primarily for reading server-side,
local storage can only be read by the client-side. So the
question is, in your app, who needs this data — the client or the
server?

If it's your client (your
JavaScript), then by all means switch. You're wasting bandwidth by sending all the data
in each HTTP header.

If it's your server, local
storage isn't so useful because you'd have to forward the data along somehow (with Ajax
or hidden form fields or something). This might be okay if the server only needs a small
subset of the total data for each
request.

You'll want to
leave your session cookie as a cookie either way
though.

As per the
technical difference, and also my
understanding:

1. Apart
   from being an old way of saving data, Cookies give you a limit of
   4096 bytes (4095, actually) — it's per cookie. Local
   Storage is as big as 5MB per domain — href="https://stackoverflow.com/questions/2989284/max-size-of-localstorage-values">SO
   Question also mentions
   it.




2. localStorage
   is an implementation of the Storage Interface. It stores data
   with no expiration date, and gets cleared
   only through JavaScript, or clearing the Browser Cache /
   Locally Stored Data — unlike cookie
   expiry.