Visual Force Important Points

* Custom controller executes entirely in system mode in which Object level, Field level permissions and sharing rules of the current user are ignored.
* Standard controller executes in user mode, in which permissions and sharing rules of the current user are enforced.
* Extending a standard controller allows you to build a Visual Force page that respects user permissions.
*Although the extension class executes in system mode, the standard controller executes in user mode.

*VF pages are compiled an rendered entirely by the Force.com platform.
* Dynamic VF components:
- <apex:datatable> in VF becomes Component.Apex.DataTable.
- <apex:outputtext> becomes,
   Component.Apex.OutputText otField = new Component.Apex.OutputText();
   otField.value='Some wild output text';
* JavaScript Remoting for Apex Controllers: To call apex methods to VF page, put @RemoteAction befor the apex methods.
*We cannot use the rerender attribute to update content in a table.
* It is not possible to create custom controller parametrized constructor
* You can't use data manipulation language (DML) operations in a “getxxx” method in a controller. For example, if your controller had a getName method, you could not use insert or update in the method to create an object.
* You can't use data manipulation language (DML) operations in a constructor method in a controller.
* You can't use the @future annotation in a “getxxx” or “setxxx” method in a controller, or in the constructor for a controller.