Salesforce visualforce is a framework for user interface that is based on the components. The visualforce is meant for building a sophisticated user interface for the purpose of providing a framework for viewing that include the markup language which is based on the tags and is similar to that of HTML.
This also comprises of a library that is full of components that are reusable and capable of extending. There is a controller model associated with the visual force that is based on the Apex.
The visualforce is something that supports the MVC that is model view controller style for the design of the user interface and is much flexible. This comprises of various standard controllers that can be made used with each of the sObject that is available in the organization.
This helps you in the creation of visualforce pages for the handling of common features without actually writing the code that is beyond visualforce. In the case of applications that are highly customized, the visualforce helps in replacing and extending the standard controller that is associated with Apex code. The applications of visualforce can be made available within the company or for publishing on web.
The simple salesforce visualforce controllers are the ones that comprises of a group of instructions that are meant for specifying the things that can happen when user is interacting with components that are specified with the markup of visualforce. They can be helpful in proving access to data which is displayed over the page and also in the modification of the behaviour associated with component. The standard controller is a type of controller that is meant for the purpose of having the similar logic and functionality that can be made used in the page of standard salesforce.
Custom controller logic can be helpful in the class that is written in Apex which can be implemented in the logic of the page. Custom controller can be helpful in defining the behaviours and elements of the navigation. It is necessary for you in the reimplementation of any functionality that is also provided by the standard controller.
Use of Visualforce Page
There are various uses associated with the simple salesforce visualforce page. The first and foremost use of such a page is in the overriding of standard buttons like save and new. The accounts tab home page and such kind of tabs are overridden in this page. The custom tabs are defined in the page and the components are embedded in the page layouts in detail.