Yii is a high-performance PHP framework best for developing web applications, provides Fast, Secure and ProfessionalPHP Framework.
YII has the features like MVC,DAO/ActiveRecord, , scaffolding,authentication and role-based access control, caching testing and so on. It is light weight and has powerful caching support. Security is a part of this frame work. It includes input validation, SQL injection output filtering, and Cross-site scripting prevention.Zend Framework (ZF) is an open source, object-oriented web application framework implemented in PHP 5