Question

A few questions regard HTML5’s sessionStorage:

• Does the 5MB limit on localStorage include sessionStorage? (ie. is it really a 5MB limit on the WebStorage API)
• If not does sessionStorage have a maximum size limit similar to localStorage?

I found this site http://dev-test.nemikor.com/web-storage/support-test/ in another SO questions, I’m wondering if the data is still relevant?

Answer 1

1. Does the 5MB limit on localStorage include sessionStorage? (Answer: NO)
2. is it really a 5MB limit on the WebStorage API (Answer: NO; Supported By )
3. does sessionStorage have a maximum size limit similar to localStorage? (Answer: NO; Supported By )

Hope I answered all your questions in a simplified manner. Here is a particularly informative section for you:

QUOTAS

You can imagine the chaos if any website was allowed to
populate unsuspecting hard drives with gigabytes of data! Thus,
browsers impose limits on storage capacity. When your app attempts to
exceed that limit, the browser will typically show a dialog to let the
user confirm the increase. You might expect the browser to enforce a
single limit for all storage an origin can use, but the major browsers
are actually enforcing limits separately for each storage mechanism.
This may change in the future, but for now, you should think of the
browser as maintaining a 2-D matrix, with “origin” in one dimension
and “storage” in the other. For example, “http://abc.example.com” is
allowed to store up to 5MB of Web Storage, 25MB of Web SQL Database
Storage, and forbidden to use Indexed Database. Another welcome
enhancement in this area would be user interfaces to let users view
and control how much space they have allocated for each origin. There
are also environments where the user can see upfront how much storage
will be used, e.g. in the case of the Chrome Web Store, when a user
installs an app, they will be prompted upfront to accept its
permissions, which include storage limits. One possible value is
“unlimited_storage”.

The above text taken from http://www.html5rocks.com/en/tutorials/offline/storage/