SGML vs XHTML: Difference and Comparison

Markup techniques such as SGML and XHTML are also regarded to be markup linguistics. A markup language is a system of words and lexical items used in digital technology to emphasize content and specify it for a web publication.

It’s critical to comprehend the responsibilities of the SGML and XHTML languages in new website creation; they have a unique relationship.

The link between these two languages is seen as a familial connection that aids in the operation of webpages and the adaptive and dynamic design of websites. Hence, the differences between both the markup languages are quite distinct and important too.

Key Takeaways

  1. SGML serves as a markup language for defining document structures, while XHTML is an application of XML that represents HTML.
  2. SGML allows for flexible syntax and custom Document Type Definitions (DTDs), but XHTML has strict syntax rules and uses predefined DTDs.
  3. Unlike SGML documents, XHTML documents can integrate with other XML-based languages and are easily processed by XML parsers.


SGML is an older markup language. It is a general-purpose language that can be used to define the structure of any type of electronic document, including web pages, technical manuals, etc. XHTML, is a newer markup language. It is designed to be more compatible with newer web technologies.


Standard generalized markup language, the full form of SGML, is a metalanguage that is a global standard for the specification of markup languages. Markup is made up of tags that describe the purpose of a string of words or how it should be represented in the final webpage.

The focus in SGML focuses on descriptive markups, such as the tag “emphasis>.” The document functionality is denoted by this markup, which can be read as inverted video on a computer monitor, typewriter highlighting, or italics in typeset text.

EXtensible HyperText Markup Language is an acronym for XHTML. It’s a language that combines HTML and XML.

XHTML is remarkably similar to HTML, although it is more stringent. HTML that is specified as an XML program is known as XHTML.

All major web browsers are compatible with it. While XHTML is nearly identical to HTML, it surely is more crucial to write good code since XHTML has tighter syntax, including case sensitivity, when compared to HTML.

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Comparison Table

Parameters of ComparisonSGMLXHTML
AcronymStandard Generalized Markup LanguageEXtensible HyperText Markup Language.
Sustenance and SupportSGML is low sustenance because of its complex UI and stringent codes.XHTML is a very sustainable markup language which is used 
SpeedSGML is slow to load and refreshXHTML is fast to load, and many web pages are compatible with it.
OriginSGML is a descendant of IBM’s Generalized Markup Language (GML), which was created in the 1960s by Charles Goldfarb and team.26th January 2000 in version 5.0, with the latest release in October 2014.
VersionsNo version bifurcations, however, the document contains; a declaration, prologue and DTD. XHTML; 1.1, 2.0, 2.1, 5.0 etc.

What is SGML?

The Standard Generalized Markup Language (SGML) is an acronym for SGML. SGML is the primary language of HTML as well as XML, all of which are currently commonly used for electronic document transcription.

The appeal of SGML has grown quickly over time in a variety of specialized domains. SGML has a few limitations as well.

Due to SGML’s robust settings, an unreliable program is generated because there are no commonly accepted style sheets.

Furthermore, SGML data transfer has grown extremely complicated as a result of variable complete software interoperability, which can lead to major issues.

For these drawbacks, cynics have dubbed SGML “Sounds Good Maybe Later.”

DTDs are specified using SGML (document type definitions). A DTD specifies a kind of text, such as a reporting study, by describing which components must occur in the document—for example, Title>—and by establishing rules for the use of document components, such as the fact that an article may exist within a table entry but not really a table.

A parsing program can examine a marked-up text to see if it adheres to a DTD. Other applications may scan the markups in order to create indexing or convert the page to PostScript for publishing it using SGML for the final webpage.

However, the operations and methods for coding using SGML language are pretty complicated and tough when compared to the simplistic XML language.

What is XHTML?

XHTML is a precursor of HTML 4.0 that was created as a conceptualization. Later, a variant of HTML was created to create a variety of digital information.

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There are numerous reasons why content providers choose to produce XHTML. This language was created to allow users to create their custom tags.

XHTML is a portable markup language. As a result, non-desktop users can use the technology to browse these electronic files.

As a result, XHTML is an XML product, whereas HTML is an SGML result. XML was also created with the intention of being expandable.

As a result, XHTML has also become extensible. XML Document Descriptions, or DTDs, were established by XML in the instance of SGML. The father of XML and its variants can be said to be SGML.

XHTML stands for ‘EXtensible HyperText Markup Language’, a language combining HTML and XML. XHTML is remarkably similar to HTML, although it is more stringent. XHTML is much more long-lasting than SGML.

Web apps are growing more complex with experience. As a result, XHTML will gain wide acceptance.

A large number of programs implement the usage of XHTML. As a result, it may be used to build complicated websites.

The few computers that can handle XHTML are operating quicker due to reduced error process parameters. Files with a high number of mistakes take longer to process.

Main Differences Between SGML and XHTML

  1. SGML is complex, whereas XHTML is more sustainable and user-friendly than SGML.
  2. SGML stands for Standard Generalized Markup Language, whereas XHTML stands for EXtensible HyperText Markup Language.
  3. SGML does not permit conversion to other file types, such as PDF, RSS, or RFT, but XHTML does.
  4. SGML does not imply any closing tags, whereas XHTML supports closing tags.
  5. SGML-based webpages are slow to load and sometimes require more threshold support, whereas XHTML is fluidic and faster to load.

Last Updated : 11 June, 2023

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11 thoughts on “SGML vs XHTML: Difference and Comparison”

  1. The comparison table provided is very informative. It clearly outlines the differences between SGML and XHTML across various parameters.

  2. The discussion of DTDs in SGML is particularly intriguing. This article offers valuable insights into the complexities of SGML document structure and functionality.

  3. The link between SGML and XHTML is fascinating. It’s interesting to see how SGML has more flexible syntax and custom DTDs, while XHTML has strict syntax rules and predefined DTDs.

  4. Thank you for the insightful comparison between SGML and XHTML. It’s crucial to understand the differences and the roles of these markup languages in web development.

  5. I appreciate the thorough discussion on the origins and versions of SGML and XHTML. Understanding the history of these languages provides valuable context for their use in modern web development.

    • Absolutely, knowing the origins and evolution of these languages helps us appreciate their significance in the current digital landscape.

    • I couldn’t agree more. The historical context of SGML and XHTML enhances our understanding of their applications today.

  6. The detailed explanation of SGML and XHTML is enlightening. It’s important to understand how SGML focuses on descriptive markups while XHTML is a more stringent language.

  7. The comparison between SGML and XHTML, especially in terms of speed and sustenance, is essential information for web developers. The distinction between the two languages is clearly articulated in this article.

  8. SGML and XHTML both play significant roles in web publication and their differences are worth noting. This article provides a comprehensive overview of their functionalities.


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