HTML vs. XHTML
Explain whether <br /> in a text/html document makes it XHTML.
Understand the topic
HTML and XHTML have different parsing rules. Normal text/html documents use the HTML parser, which can recover from many syntax errors. XHTML uses XML syntax and, when served as XML, requires well-formed markup with stricter handling of errors. Writing a slash on an HTML void element does not switch the document to XML parsing.
Worked example
<!-- HTML syntax -->
<input type="text" required>
<br>
<!-- XML-style syntax -->
<input type="text" required="required" />
<br />The response media type determines how the browser parses a document. Modern HTML authoring normally uses text/html with the short doctype.
Practice
Explain whether <br /> in a text/html document makes it XHTML.
Show a suggested answer
No. The document is still parsed as HTML. XML-style spelling alone does not change its media type or parser.Common mistake
Do not rely on HTML error recovery when serving an actual XML document. A well-formedness error can prevent rendering.