HTML (Hypertext Markup Language) and XHTML (Extensible Hypertext Markup Language) are both markup languages used for structuring and presenting content on the web. While they share many similarities, there are some key differences between the two.
- Syntax: HTML and XHTML have different syntax rules. HTML has a more forgiving syntax, allowing certain errors and inconsistencies, while XHTML has a stricter syntax that follows the rules of XML. XHTML requires well-formed and valid markup, including properly nested elements and closing tags.
- Document Structure: In HTML, elements can be self-closing, meaning they don’t require a closing tag. For example, in HTML, you can write
<br>to represent a line break. In XHTML, all elements must have closing tags, so it would be written as<br />. - Case Sensitivity: HTML is case-insensitive when it comes to element and attribute names. XHTML, on the other hand, is case-sensitive, requiring lowercase element and attribute names.
- XML Conformance: XHTML is based on XML, which means it adheres to XML rules and can be parsed by XML processors. HTML, on the other hand, has a looser structure and doesn’t conform to XML standards.
- MIME Types: HTML is typically served with the MIME type “text/html”, while XHTML is served with the MIME type “application/xhtml+xml”. The difference in MIME types affects how the documents are processed by web servers and browsers.
- Compatibility: HTML has wider browser support and is compatible with older browsers that may not handle XHTML properly. XHTML is recommended for stricter adherence to web standards and compatibility with XML-based tools and technologies.
Overall, the choice between HTML and XHTML depends on factors such as the level of strictness and conformance required, compatibility with existing systems, and the target audience. HTML is more forgiving and widely supported, making it suitable for general web development. XHTML is preferred when strict XML compliance is necessary or when working with XML-based technologies.
Let’s compare HTML and XHTML using an example:
HTML Example:
<!DOCTYPE html>
<html>
<head>
<title>HTML Example</title>
</head>
<body>
<h1>Welcome to HTML</h1>
<p>This is an example of HTML markup.</p>
<img src="image.jpg" alt="Image">
</body>
</html>XHTML Example:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>XHTML Example</title>
</head>
<body>
<h1>Welcome to XHTML</h1>
<p>This is an example of XHTML markup.</p>
<img src="image.jpg" alt="Image" />
</body>
</html>In the HTML example, we have a typical HTML document structure. The <h1> tag represents a heading, the <p> tag represents a paragraph, and the <img> tag is a self-closing tag for an image. HTML doesn’t require all elements to have closing tags, and the case of the tags and attributes is not significant.
In the XHTML example, we have an XHTML document with a stricter syntax. The XML namespace declaration (xmlns="http://www.w3.org/1999/xhtml") is added to indicate that the document follows the XHTML rules. All elements in XHTML must have closing tags, including the <img> tag, which is closed with a self-closing slash (/>). Additionally, XHTML requires lowercase tag and attribute names to be used.
The examples demonstrate the key differences between HTML and XHTML. While the HTML example is more lenient and forgiving, the XHTML example follows stricter syntax rules and XML standards. The choice between HTML and XHTML depends on factors such as the desired level of conformance, compatibility requirements, and target audience.