Chapter 9. Extending the Engine

Using an object-oriented design for the Ajax engine provided us with the flexibility to extend or incorporate the code into any web application. The engine that we have created can accomplish any type of request. To make this engine extremely powerful, we can create additional objects that extend the engine's functionality and provide us with ways of handling common situations when developing our Ajax applications.

This chapter will focus on extending the Ajax engine with two completely different types of objects. The first object that we will create is a Utilities object, which will handle all of the common front-end functionalities, such as creating HTML elements, simplifying common JavaScript functions, and providing our applications with reusable GUI-focused methods. The second object is an HTTP object, which will handle all the possible status codes that may be returned with the Ajax response. Although the Utilities object is completely focused on front-end code, this object has the dual purpose of providing both the front end and back end with appropriate status code responses as strings.