Web Storage

Web storage and DOM storage (Document Object Model storage) are web application software methods and protocols used for storing data in a web browser. Web storage supports persistent data storage, similar to cookies but with a greatly enhanced capacity and no information stored in the HTTP request header. There are two main web storage types: local storage and session storage, behaving similarly to persistent cookies and session cookies respectively.

Web storage is being standardized by the World Wide Web Consortium (W3C). It was originally part of the HTML5 specification, but is now in a separate specification. It is supported by Internet Explorer 8, Mozilla-based browsers (e.g., Firefox 2+, officially from 3.5),Safari 4, Google Chrome 4 (session storage is from 5), and Opera 10.50. As of 14 March 2011^[update] Opera and IE9 support the storage events.

Web storage can be viewed simplistically as an improvement on cookies. However, it differs from cookies in some key ways.

Web storage provides far greater storage capacity (5 MB per origin in Google Chrome,Mozilla Firefox, and Opera; 10 MB per storage area in Internet Explorer; 25MB per origin on BlackBerry 10 devices) compared to 4 kB (around 1000 times less space) available to cookies.