You can validate the RoboHelp generated XHTML code against W3C specifications for compliance with XHTML Transitional 1.0. Right-click a topic in the Project Manager and choose Validate W3C Compliance to validate the topic. You can select Validate All to validate all the topics.
The following features are not supported in XHTML:
•Marquees in topics
•Border color in framesets
•Background sound in topic properties
Use of these features results in invalid XHTML code. Remove these features to generate valid XHTML code.