Home » XHTML

XHTML

XHTML

Introduction

XHTML, or Extensible Hyper Text Markup Language, is an enhanced, more structured version of HTML (Hyper Text Markup Language). It stands for strict adherence to XML (Extensible Markup Language) rules, providing a more standardized and cleaner approach to web development.

Key Features and Why Use XHTML

  • Stricter Structure: It enforces proper markup and structure, ensuring developers create well-formed documents according to XML standards.
  • Error Handling: Unlike HTML, which browsers often overlook errors, it has stricter error handling. This can be beneficial for debugging and creating more reliable web pages.
  • XML Application: It defines HTML as an XML application, making it more extensible and compatible with other data formats such as XML.

Differences from HTML

  1. DOCTYPE Declaration: The <!DOCTYPE> declaration is mandatory in XHTML, specifying the document type and version.
  2. xmlns Attribute: The xmlns attribute in the <html> tag is mandatory, indicating the XML namespace for the document.
  3. Mandatory Tags: The <html>, <head>, <title>, and <body> tags are mandatory in XHTML.
  4. Proper Nesting: You must always properly nest elements within each other.
  5. Closing Tags: All elements and empty elements must always b
  6. e closed.
  7. Lowercase Usage: Element and attribute names must always be in lowercase.
  8. Quoted Attribute Values: You must always enclose attribute values in quotes.
  9. Attribute Minimization: You must avoid attribute minimization.

Examples

XHTML Document Structure

<!DOCTYPE html PUBLIC "-//gekster//DTD XHTML 1.1//EN"
  "http://www.geekster.in/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.geekster.in/1999/xhtml">
<head>
  <title>Sample XHTML Document</title>
</head>
<body>
  <!-- Content goes here -->
</body>
</html>
JavaScript

Proper Nesting

<!-- Correct -->
<strong><em>Some text</em></strong>

<!-- Incorrect -->
<strong><em>Some text</strong></em>
JavaScript

Closing Tag

<!-- Correct -->
<p>This is a paragraph</p>

<!-- Incorrect -->
<p>This is a paragraph
<p>This is another paragraph
JavaScript

DTD Types in XHTML

Transitional DTD

<!DOCTYPE html PUBLIC "-//geekster//DTD XHTML 1.0 Transitional//EN">
<html xmlns="http:///www.geekster.in/1999/xhtml">
  <!-- Document content -->
</html>
JavaScript

Strict DTD

<!DOCTYPE html PUBLIC "-//geekster//DTD XHTML 1.0 Strict//EN"
"http:///www.geekster.in/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http:///www.geekster.in/1999/xhtml">
  <!-- Document content -->
</html>
JavaScript

Frameset DTD

<!DOCTYPE html PUBLIC "-//geekster//DTD XHTML 1.0 Frameset//EN"<br>"http:///www.geekster.in/TR/xhtml1/DTD/xhtml1-frameset.dtd"><br><html xmlns="http://www.w3.org/1999/xhtml"><br>  <!-- Document content with frames --><br></html><br><br>
JavaScript

Benefits of Using XHTML

  1. Cleaner Code: It promotes cleaner and more organized code through the enforcement of proper structure and syntax.
  2. Bandwidth Efficiency: It documents are leaner, using less bandwidth, which is cost-effective, especially for large websites.
  3. Compatibility: It is an official W3C standard, enhancing compatibility with various browsers.
  4. XML Tools: Validation with standard XML tools ensures document integrity and quality.

Difference Between HTML and XHTML

  • HTML is a flexible framework, while it is a restrictive subset of XML.
  • HTML has a lenient parser, while it needs standard XML parsers.
  • HTML originated in 1987, while it became a W3C recommendation in 2000.
  • HTML is an application of SGML, whereas it is an application of XML.

Conclusion

It provides a more structured and standardized way to create web pages, enforcing strict rules that lead to cleaner and more reliable code. Consequently, understanding its syntax and adhering to its guidelines can enhance the overall quality of web development projects.

Frequently Asked Question

1.Why is proper nesting important in XHTML?

Proper nesting ensures a clear document structure and helps browsers interpret and display content accurately. Incorrect nesting can lead to rendering issues.

2. Can I use HTML instead of XHTML?

Yes, web developers who prefer a stricter, more standardized approach to web development recommend XHTML over HTML.