Forms are a key feature of any application that makes use of Visualforce. They provide a mechanism to capture data entered by the user and send this to the page controller for processing, for example, to create, edit, or delete sObject records, or to send the user to a specific page.
Users enter data through input components. Visualforce provides a specific standard component, <apex:inputField />, for entering sObject field data. This component renders the appropriate device for entering data based on the field type, such as a JavaScript date picker for a field of type Date. Input components are bound to sObject fields or controller properties via the merge syntax. Controller properties that are public and have a public getter and setter may be bound to input components without writing any further code.
Processing of the submitted form is carried out via Action methods. These may be provided automatically by the platform in the case of standard controllers, or coded using...