4. Adding Functionality with Libraries br br What are CodeIgniter libraries? br br In computer science, a library is a collection of functionality that serves a specific purpose with a well defined interface and logical structure. CodeIgniter comes with several dozen libraries for common tasks. Each implemented as a class. Examples of classes include the input class, form validation class and HTML table class. To use a library, it needs to be initialized within a controller using the following initialization method: this - load -library, followed by a string containing the machine name of the library. br br For example, formvalidation. Multiple libraries can be initialized at once by passing an array of strings containing the names of the libraries to load. Such as form validation and table. Each library has a dedicated page within the CodeIgniter User Guide, which includes usage examples and a function reference. In this chapter, I'm going to allow users to add magazines using a form, then validate those forms including some custom validation. After that, I'll use a number of CodeIgniter libraries to accept user input and list magazines in a generated HTML table. br br Let's get started.