XHTML Quiz

XHTML requires all attribute names and values to be in lowercase, and attribute values must be quoted. The correct format is width="80" (all lowercase, quotes around value). Option B is correct. Options A and D use uppercase, and option C lacks quotes.

XHTML is stricter than HTML - every element must be properly closed, including empty elements which use self-closing syntax like
or . This is a fundamental rule that distinguishes XHTML from HTML.

The DOCTYPE declaration is not an HTML/XHTML element - it's a document type declaration that tells the browser which version of HTML/XHTML to use. Declarations, unlike elements, do not have closing tags.

XHTML documents require a complete structure: the DOCTYPE declaration at the top, then as the root element, which must contain and sections. The section must contain a

In XHTML, tags must be properly nested - inner tags must close before outer tags close. Option A has closing after , which violates nesting. Option C uses

For XHTML documents that serve as XML (application/xhtml+xml), the xml:lang attribute is required for language declaration. For compatibility with HTML user agents, both lang (HTML) and xml:lang (XML) should be specified. Option B uses xml:language which doesn't exist, and option C uses 'language' which isn't a valid attribute.

XHTML 1.0 defines three Document Type Definitions (DTDs): Strict (no deprecated elements), Transitional (allows deprecated elements for compatibility), and Frameset (for documents with frames). 'Loose' is not a valid DTD type in XHTML.

The Transitional DTD is the most commonly used because it supports deprecated HTML elements and attributes while still enforcing XHTML's stricter syntax rules. This provides a migration path from HTML to XHTML without requiring immediate cleanup of legacy markup.

Yes - all XHTML documents must include a DOCTYPE declaration to be valid. The DOCTYPE tells the validator and browser which DTD to use for validation and rendering. Without it, the document is not valid XHTML.

XHTML is case-sensitive and requires all element and attribute names to be in lowercase. This is different from HTML, which is case-insensitive. Writing