...It's flexible enough to create full-stack frameworks, micro-frameworks or advanced CMS systems like Drupal. Every HTTP web interaction begins with a request and ends with a response. Your job as a developer is to create PHP code that reads the request information (e.g. the URL) and creates and returns a response (e.g. an HTML page or JSON string). Typically, some sort of framework or system is built to handle all the repetitive tasks (e.g. routing, security, etc) so that a developer can build each page of the application. Exactly how these systems are built varies greatly. ...