Log in to like this post! Ignite UI and NetAdvantage for ASP.NET DOCTYPE Support [Infragistics] Aaron Marisi / Thursday, April 11, 2013 Web browsers determine how to render the markup of a web document using the Document Type (DOCTYPE) Declaration. The DOCTYPE must be placed at the top of the document and should appear as specified by the W3C. The following are the supported DOCTYPE declarations for Ignite UI® and NetAdvantage® for ASP.NET as well as further DOCTYPE considerations. Ignite UI Ignite UI is a set of components based on modern web technologies and specifications. The components are fully tested to work with an HTML5 DOCTYPE. <!—- HTML5 --> <!DOCTYPE html> NetAdvantage for ASP.NET The NetAdvantage for ASP.NET product has a rich history and began when the .NET Framework CLR 1.0 was still in use. During the years following, developers used various recommended DOCTYPE declarations in their applications. Currently to ensure the highest compatibility for NetAdvantage for ASP.NET components, use either an HTML5 or an XHTML 1.0 transitional DOCTYPE. <!—- HTML5 --> <!DOCTYPE html> <!—- XHTML 1.0 Transitional --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> Quirks Mode Quirks mode rendering is the browser default when there is a missing or malformed DOCTYPE declaration. Modern browsers support this for legacy purposes but it is not recommended for modern web applications nor supported with Infragistics® controls. Other DOCTYPE Declarations Using a different DOCTYPE than listed above does not guarantee the controls perform incorrectly and you should decide carefully how to use DOCTYPE declarations in your application. Furthermore because support for all variations of DOCTYPES is not possible, it is recommended to use the declarations listed above.