Today I was looking into web storage (localStorage) feature introduced in HTML5. Most of the modern browsers provide means through which key/value pairs can be securely stored and retrieved for later use. Browser cookies can indeed be used for the storage of persistent data but are limited in capacity. Also with cookies, the data is transmitted in every HTTP request thereby making the web applications run slow. Unlike cookies, in local storage there is no limit on the size of the data and it is never transmitted to the web server unless an attempt is made to send it manually. Whenever the data in the storage area changes a ' storage ' event is fired. This event is fired whenever the methods setItem(), removeItem(), or clear() are called on the localStorage object. However, when I tried to use these methods to update the localStorage area, the storage event never fired: The methods setItem and clear did change the storage area and I confirmed this by referring to the resour