Check the current document or a selected tag for tag or syntax errors. Dreamweaver can validate documents in many languages, including HTML, XHTML, ColdFusion Markup Language (CFML), JavaServer Pages (JSP), Wireless Markup Language (WML), and XML.
You can set preferences for the Validator, such as specifying the tag-based languages against which the Validator should check, the specific problems that the Validator should check for, and the types of errors that the Validator should report. For more information, see Set the Validator preferences.
For an XML or XHTML file, select File > Check Page > Validate as XML.
Select File > Check Page > Validate Markup.
The Validation tab of the Results panel displays a “No errors or warnings” message or lists the syntax errors it found.