XHTML (Extensible Hypertext Markup Language) is a reformulation of HTML using XML (Extensible Markup Language). It is stricter than HTML and ensures well-formed documents that are more consistent and reliable across different platforms.
Key Features
- Combines the flexibility of HTML with the strict syntax rules of XML.
- Ensures well-formed documents that are easy to parse.
- Designed to be more extensible for future web technologies.
- Supports better integration with other XML-based languages (e.g., SVG, MathML).
Pros & Cons
Advantages
- Well-Formed & Strict Syntax: Fewer errors, easier debugging.
- Extensibility: Can integrate with XML, SVG, MathML.
- Backward Compatibility: Works with older HTML browsers.
- Improved Accessibility: More structured content.
Disadvantages
- Stricter Rules: Requires well-formed markup.
- Deprecated in Favor of HTML5: HTML5 offers similar benefits without strict XML rules.
- More Verbose: Requires explicit closing tags and attributes.
HTML vs XHTML
| Feature | HTML | XHTML |
|---|---|---|
| Case Sensitivity | Not case-sensitive (<BR> = <br>) | Case-sensitive (<br> only) |
| Element Closing | Optional in some cases (<p>Text) | Mandatory (<p>Text</p>) |
| Attribute Quotes | Optional (width=100) | Required (width="100") |
| Attribute Minimization | Allowed (<input checked>) | Not Allowed (<input checked="checked">) |
| Nesting Rules | Lenient | Strictly follows XML rules |
| Doctype Declaration | Multiple formats | Strict doctype required |