What is HTML5 Web Storage?

With HTML5, it is possible for the web pages to store the data locally in the user's browser. This web storage is much faster and secured than the cookies. Also, a larger amount of data can be stored without causing any adverse effect to the performance of the website.
The data here is not included with every server request. It is used ONLY when it is asked for. It is only that particular web page that can access the data stored by itself.