What are some differences that XHTML has compared to HTML?

XHTML, or Extensible Hypertext Markup Language, differs from HTML (Hypertext Markup Language) in several key ways:

1. Syntax Strictness: XHTML is much stricter in terms of syntax compared to HTML. In XHTML, all elements must be properly nested, attributes must be quoted, and all tags must be closed. For example, in HTML, it is permissible to use <br> for a line break, whereas in XHTML, you must use <br />[1][2][4].

2. Case Sensitivity: XHTML is case-sensitive, meaning that all tags and attributes must be written in lowercase. HTML, on the other hand, is not case-sensitive[2][5].

3. Document Structure: XHTML documents must have a root element that encloses all other elements, and they must strictly follow the XML structure. This is not a requirement in HTML where elements can be more loosely organized[1][2][4].

4. Compatibility and Extensibility: XHTML was developed to be more compatible with XML, allowing for easier integration and transformation of data across different XML applications. This makes XHTML more suitable for data-driven applications where XML is commonly used[2][4].

5. DOCTYPE Declaration: XHTML requires a DOCTYPE declaration at the beginning of the document to ensure that ...