CodeIgniter is not a PHP substitute. When you dive into the world of CodeIgniter, you’re not leaving PHP behind—and why would you want to? PHP5 is a doozy of a scripting language for building state-of-the-art, dynamic web-based applications; its rapport with HTML is top-notch; plus it’s a great language for honing your OOP skills. It’s tight, secure and intuitive. For many of us, it’s the only server-side language for our needs.
CodeIgniter is a PHP-driven framework, containing a grab-bag of libraries, helpers, plug-ins and other resources, that takes care of many of the more complex procedures and functions for which PHP is famous. CodeIgniter does all the heavy lifting for you while maintaining high performance. It will simplify PHP syntax, streamline the code underlying your web pages, and—best of all—have you churning out dynamic, interactive, professional websites in no time.