XHTML (Extensible Hypertext Markup Language) is a markup language that is a stricter and cleaner version of HTML. It is designed to be a more robust and standardized format for web pages, adhering to the rules of XML (Extensible Markup Language). This means that XHTML documents must be well-formed, with properly nested tags, closing tags for all elements, and correctly quoted attributes. XHTML aims to provide a more consistent and predictable rendering of web pages across different browsers and platforms. It enforces stricter syntax rules than HTML, which helps to reduce errors and improve the overall quality of web content. XHTML was intended to replace HTML, but HTML5 has since become the dominant standard. However, XHTML is still used in some contexts, particularly where XML-based processing is required or where strict validation is important. XHTML documents are typically served with a MIME type of application/xhtml+xml, which tells the browser to parse the document as XML.