What are the differences between HTML5, HTML4.01, and XHTML 1.0?
sobes.tech AI
Answer from AI
HTML5 is the latest version of HTML with new elements (semantic elements like <article>, <section>), support for multimedia (<video>, <audio>), APIs for geolocation, web storage, and offline applications. It is more tolerant of syntax errors and backward compatible.
HTML4.01 is the previous standard with less strict syntax rules compared to XHTML. It does not support the new features of HTML5 out of the box.
XHTML 1.0 is HTML rewritten as an XML application. It requires strict adherence to syntax rules (e.g., closing all tags, using lowercase for element and attribute names, mandatory quotes for attribute values). It was developed for greater extensibility and compatibility with XML processing tools.
The main differences can be grouped as follows:
- Syntax: HTML5 is the most flexible, XHTML 1.0 is the strictest (XML-compatible), HTML4.01 is in between.
- Semantics: HTML5 includes new semantic tags for better content structure.
- Functionality: HTML5 adds many APIs for interactive web applications.
- Error handling: HTML5 has clearer error handling rules, browsers recover more easily from incorrect syntax.
- Document type (DOCTYPE): In HTML5, it is much simpler:
<!DOCTYPE html>. In HTML4.01 and XHTML 1.0, they are longer and specify the used DTD (Document Type Definition).
Example DOCTYPE:
<!DOCTYPE html>
<!-- HTML5 -->
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<!-- HTML 4.01 Transitional -->
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- XHTML 1.0 Strict -->
Comparison table:
| Feature | HTML5 | HTML4.01 | XHTML 1.0 |
|---|---|---|---|
| Syntax | Flexible | Moderately strict | Strict (XML-based) |
| DOCTYPE | <!DOCTYPE html> |
Long (specifies DTD) | Long (specifies DTD) |
| Semantics | New semantic tags | Less semantics | Less semantics (compared to HTML5) |
| Multimedia | Built-in support (<video>, <audio>) |
Requires plugins | Requires plugins |
| API | Many new APIs | Limited | Limited |
| Error handling | Defined and predictable | Less predictable | Requires strict syntax adherence |
| XML compatibility | Not required | Not required | Compatible |