Master Pages

Difference between Master Page and normal .ASPX page

A Master Page can contain the same Web controls, User controls, HTML content, and scripts that can be added to a standard ASP.NET page. There are three important differences between a Master Page and a normal ASP.NET page.

First, unlike a normal ASP.NET page, the name of a Master Page must end with the special extension .master. This extension marks the page as a Master Page. Furthermore, an ASP.NET application is configured so that you cannot request pages with the .master extension.

Second, a Master Page includes a <%@ Master %> directive instead of the normal <%@ Page %> directive. The <%@ Master %> directive supports many of the same attributes as the<%@ Page %> directive. For example, you can specify the programming language of the page with the directive <%@ Master Language="vb" %>.

The final difference between a Master Page and a normal ASP.NET page is that a Master Page can contain zero or more ContentPlaceHolder controls. A ContentPlaceHolder control can be used only within a Master Page. This control marks an area of a Master Page that can be overridden by a particular content page.