xhtmlConformance Element (ASP.NET Settings Schema)

Configures XHTML 1.0–conforming control rendering.

<xhtmlConformance mode="Transitional|Legacy|Strict"/>

The following sections describe attributes, child elements, and parent elements.


Attribute Description


An optional String attribute, which specifies the XHTML rendering mode for an ASP.NET application. The mode can be one of the values listed in the following table. The default is Transitional (XHTML 1.0 Transitional).

Value Description


XHTML 1.0 Transitional


XHTML 1.0 Strict conformance


Reverts a number of rendering changes made for conformance to the v1.1 rendering behavior.

Child Elements


Parent Elements

Element Description


The required root element in every configuration file that is used by the common language runtime and .NET Framework–based applications.


Specifies the root element for the ASP.NET configuration settings in a configuration file. Contains configuration elements that configure ASP.NET Web applications and control how the applications behave.

By default, when you are working with browsers that support HTML 4.0 or later, ASP.NET pages and controls render markup that is compatible with the XHTML 1.0 Transitional standard. However, under some circumstances, you might not want ASP.NET to render XHTML markup. This is typically true when you have existing pages that rely on tags or attributes that would ordinarily be prohibited by XHTML.


Only rendering changes that are likely to break existing applications are reverted to their old behavior. There is no mechanism to revert all changes made to comply with the XHTML specification.

The following default xhtmlConformance element is not explicitly configured in the machine configuration file or in the root Web.config file, but is the default configuration returned by an application in the .NET Framework version 2.0.

<xhtmlConformance mode="Transitional"/>

The following code example switches the rendering mode to conform to the XHTML 1.0 strict standard. The key change that occurs is that the name attribute is no longer rendered on the form tag.

<xhtmlConformance mode="Strict"/>

Configuration Section Handler


Configuration Member


Configurable Locations


Root-level Web.config

Application-level Web.config



Microsoft Internet Information Services (IIS) version 6.0

Microsoft .NET Framework version 2.0

Microsoft Visual Studio 2005

Community Additions