In Serna, you can work with valid documents and with well-formed documents. A valid document conforms with XML syntax and uses a DTD/ Schema. A well-formed document conforms with XML syntax but doesn't use a DTD/ Schema.
If a document is opened or created with an XML Schema, it is dynamically validated, or validated on-the-fly. This means Serna helps the user by providing the following:
Lists of available elements and attributes for insertion.
Reports on creating invalid content (elements, attributes, text).
Automatic creation of unambiguously required elements.
Choose element boxes that indicate that at this position an element is required, but the user must manually choose the required element from the list.
No validation is performed.
Document is dynamically validated, but the user may create invalid content (element, attributes, etc). Serna only signals errors in the Message Window.
Document is dynamically validated, and Serna does not allow the user to perform invalid operations. When you attempt to create invalid content, Serna undoes the operation.
Strict validation mode is recommended for inexperienced authors of XML documents.
To switch validation modes, choose Strict, On, or Off.
and select one of the modes: