HTML5 APPLICATIONS DEVELOPMENT MANUAL

In HTML5, developers can use the Web storage instead, which offers

more flexibility, larger data sets, and better performance. The localStorage

method allows users to save larger amounts of data from session to s ession

(persistent data), and there’s no time limit as to how long the data exists.

The SessionStorage method keeps data only for one session (until the

browser is closed), which is also referred to as “per-tab storage.” Using these

methods, specific data is transferred only when requested, so it’s possible to

store a relatively large amount of data without slowing down the connection

or site.

Appcache for offline files

Another way to use Web storage is to store data locally when a user is

offline. The Application Cache, or AppCache, stores resources like images,

HTML pages, CSS files, and JavaScript - data that would ordinarily be stored

on a server. Because the resources are stored on the client’s hard disk or

device, the resources load faster when requested.

Using AppCache, a developer uses a text file called a “cache

manifest” to specify the files a Web browser should cache offline. Even if a

user presses the Refresh button offline, the app will load and work correctly.