One of the biggest advantages of PHP programming language is its extensibility. Here is a rundown of some very useful PHP classes that can make programming really simple.

PHP PSD Reader - This class allows you to display any Adobe PSD (Photoshop Document) file on screen. It is very useful to create preview of PSDs designed for clients.

Browser Detect - One of the biggest challenges for front-end developers is cross browser compatibility. This class can help detect almost all browsers and simplify your cross browser tasks.

ADOdb - This is a database abstraction library for PHP, which supports MySQL, PostgreSQL, Interbase, Firebird, Oracle, MS SQL and more. ADOdb is easy to learn and is known for extensive portability support, speed and BSD licensing.

Akismet - This class can help you if your website gets spammed. When a new comment, trackback, or pingback comes to your site, it is submitted to the Akismet web service which runs extensive tests on the comment and returns a detection result.

HTML Purifier - This is a PHP class created to help developers write a better code by removing malicious code and determining if your code is standard-compliant.

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