15 Managing State

This chapter examines one of the most important questions in the web development world, namely, how does one request pass information to another request? This question is sometimes also referred to as the problem of state management in web applications. State management is essential to any web application because every web application has information that needs to be preserved from request to request. This chapter begins by examining the problem of state in web applications and the solutions that are available in HTTP. It then examines state management in the context of JavaScript, PHP, and Node.