Ever since Tim Berners Lee created the world’s first web page on August 16, 1991, with the help of HyperText Markup Language (HTML), the world of the Internet has grown in leaps and bounds. The initial language of HTML has undergone a lot of modifications with the passage of time, and a lot of variations have been introduced, of which Extensible HyperText Markup language is a very prominent one. The HTML and XHTML markup languages are the two most common markup languages for building web pages and applications. The most common way of creating web pages is with HTML, while XHTML is a standardized, more strict version of HTML. XHTML and HTML both have a wide range of features, which includes support for multimedia, stylesheets, and scripting, as well as formatting.
At first glance, both HTML and XHTML appear to be two faces of the same coin. But, a closer look at their features shows us that they are in fact, worlds apart. Be it their key features or characteristics, the differences between HTML and XHTML are quite obvious to point out and imperative to know about when choosing between the two. Before we get into the difference between HTML vs XHTML, it is essential for us to know what the two are. Let us get started.
What is HTML?
Tim Berners Lee developed HTML for the first time in 1993. HTML acts as the skeletal system of the web page, while Cascading Style Sheets (CSS) function as the skin on top of the bones. Without HTML, any web browser wouldn’t know how to structure the content it receives.
A markup language is a system used to elucidate the structure of a document and make it interactive and appealing to look at. It is very different from a programming language. Hypertext as the word itself suggests, means a text which links to other text, via hyperlinks. HTML or HyperText Markup Language is the language that is used in order to construct web pages from scratch.
HTML is made up of elements that are used to define the web page’s content in a structured manner. These elements come in a huge variety and are used for a plethora of reasons, depending on the task that needs to be carried out. These elements are enclosed in tags that can change the appearance of the element, or link it to some other place, and overall manipulate text, images, and other content, in order to display it in a format that we want it to be in.
Features Of HTML
The following are some of the main features of HTML:
- It is a free, lightweight, and easy-to-load markup language that is easy to learn and use.
- It can be used to add images, videos, audios, and canvases to a webpage.
- It is platform independent, as in, it can be used to display HTML files on any platform like Windows, Mac, Linux, etc.
- It can be used to add hypertext in the form of hyperlinks to web pages so that it can help readers to gain more information.
- The formatting tags help to make the design more flexible and presentable.
- Its tags and attributes can help shorten your lines of code.
What is XHTML?
Developed in January 2000 by World Wide Web Consortium (W3C), Extensible HyperText Markup Language (XHTML) is a part of the Extensible Markup Languages (XML) family. As HTML started to evolve over time, web browsers became too lenient on parsing web page source code. As a result, websites were incompletely rendered between different browsers. This was one of the major reasons why XHTML came into existence. Another reason why XHTML came into existence was to make HTML more flexible and extensible to work with data formats like Extensible Markup Language (XML).
A markup language uses ‘tags’ to determine how data is going to be presented. They’re used to represent data in a structured manner. XML is a markup language that defines a set of rules to encode documents in such a way that they can be read and understood by both humans and machines.
It helps Web Developers in order to transition from HTML to XML. Here, the developers can enter the world of XML and all of its features while still being rooted in the future compatibility of the content they are designing. Despite being extremely similar to HTML, in XHTML the code needs to be much stricter in terms of case sensitivity and syntaxes. XHTML can be considered as HTML defined as an application of XML. This too is supported by major browsers but might end up needing a stricter parser.
Features of XHTML
Let us take a look at the features of XHTML:
- In XHTML, it is easy to edit, maintain and convert the content into well-structured web pages.
- All XHTML documents are lean and use less bandwidth.
- XHTML and CSS work really well together in order to create easily updatable web pages.
- XHTML generates clean code due to its stricter standards and can be easily transported to wireless devices.
- XHTML supports a wide range of applications. Hence, it makes websites compatible and accurate with a lot of browsers.
- XHTML is XML based, which means it stores and transfers data instead of describing it.
Despite being built for the same functions at a base level, there exist some key differences between the two. Let us go through these key differences before diving off the deep end.
First off, HTML had a lot of errors that needed to be corrected when it came to the incomplete rendering of content between browsers. As a result, to address the shortcomings of HTML, development for XHTML was started. This implies that XHTML solves the shortcomings of HTML by incorporating features of XML. XHTML can be thought of as an extension of HTML. HTML is made of elements (with 3 components – pair of element tags, element attributes, and content) while XHTML has only one root element. Secondly, XHTML is a lot stricter when it comes to the file’s structure and coding. It doesn’t allow missing closing tags and overlapping of elements. XHTML doesn’t allow any underlying shortcuts while it’s allowed in HTML. Thirdly, HTML doesn’t need all the attribute values to be quoted, whereas, in XHTML it is an unavoidable necessity. XHTML provides a format that is easily parseable in comparison to that of HTML.
Other than these, there are a lot of other more subtle differences in documentation and syntaxes between the two which are not as prominent as these differences are.
Difference Between HTML and XHTML: Full Comparison
Now that we know the key differences, it is time to explore in detail the differences between HTML and XHTML. Here are some major differences between HTML vs XHTML:
|Parameter of Comparison||HTML||XHTML|
|Full Form||HTML stands for HyperText Markup Language.||XHTML stands for Extensible HyperText Markup Language.|
|Developers||It was developed by Tim Berners Lee.||It was developed by W3C – World Wide Web Consortium.|
|Initial Release Date||It was initially released in 1993.||It was initially released on 26 January 2000.|
|Format||It is in Document file format.||It has Markup Language as the file format.|
|Filename Extension||An HTML file can be saved with the extensions – .html, .htm.||An XHTML file has extensions – .xhtml, .xht, .html, .htm, .xml.|
|Source of extension||HTML is extended from Standard Generalized Markup Language (SGML).||XHTML is extended from HTML and XML. It is a sort of amalgamation between the two.|
|Type||It is of the type text/html.||It is of the type application/XHTML+XML|
|Parsing||It needs a lenient HTML-specific parser in order to parse the file.||It can be parsed with a standard XML parser.|
|Case Sensitivity||HTML files are not case-sensitive.||XHTML files are case sensitive. Everything must be in lowercase.|
|Tags||All tags need not be closed in the order of opening. Open tags can be used in an HTML file.||All tags need to be compulsorily closed in an XHTML file, in the same order that they were opened in.|
|Expressivity||HTML is less expressive in comparison to XHTML.||XHTML is more expressive with respect to HTML.|
|Root Element||HTML doesn’t call for a mandatory root element.||XHTML needs a mandatory root element to be present.|
|Content Placement||All content can be included under the body element.||Content must be placed in the form of blocks.|
|Structure of Elements||There is no defined set of rules on the structure of elements.||There is a defined set of rules which must be adhered to when it comes to the structuring of elements.|
|Attribute Values||Attribute values are not important in HTML.||These are very significant in XHTML.|
|DOCTYPE||It is not necessary to write this at the top of the file.||It is necessary to write this at the top of the file.|
|Quotes||In attributes, it’s not necessary to mention quotes.||In attributes, it is compulsory to mention quotes.|
|Consistency||HTML is less consistent than XHTML.||XHTML is more consistent than HTML.|
|Strictness||HTML is a very lenient language in comparison to XHTML.||It has really strict rules regarding coding ad structures.|
|Future Compatibility||HTML has a lower future compatibility than XHTML does.||XHTML has really good future compatibility.|
|Attribute Minimization||It is allowed in HTML.||It is not allowed in XHTML.|
|Code Structure||The code structure of HTML is slightly less organized than that of XHTML.||XHTML leads to a more organized code structure than HTML.|
|Future Proof||As websites become more and more advanced, we move towards XML. And there is a slight chance that HTML might become obsolete.||XHTML can be used for a long time, despite this gradual shift, since it is a type of XML.|
|Error Processing Routines||These are longer in HTML.||These are shorter in XHTML, so, future browsers can support faster processing.|
|Versions||HTML 1.0, HTML 2, HTML 3.2, HTML 4.01, HTML 5 are some of the different versions of HTML.||XHTML 1.0, XHTML 1.1, XHTML Basic, XHTML 1.2, XHTML 2.0, XHTML5 are some of the famous versions of XHTML.|
The above table shows us how HTML is different from XHTML. Based on what kind of purpose each of them serves, we can choose one of them and use it to perform our task.
Based on all that we have learned so far, we can say that each of these can be used in different circumstances, leading to different outcomes. HTML would be easy to learn for beginners. Based on the knowledge one acquires from HTML, one can move on to XHTML. If the user wants a more structured and stricter version of content on a web page, XHTML is the right choice, but, if the user wants a more flexible and lenient solution, HTML is the one to go with. In reality, both sides have their own version of pros and cons. Choosing one over the other would be unfair and difficult as each one of them has its own uses. But, if one had to choose between them, breaking down your needs and comparing them with the features the languages offered, can simplify your decision by a lot. Either way, having a good grasp over both of them can take you a long way in current times, with constantly changing technology.
Frequently Asked Questions
1. Is XHTML better than HTML?
Both XHTML and HTML have their advantages and disadvantages, but it’s hard to pick out a winning one. All of it depends on personal needs and the alignment of features offered by the two of them. While HTML may be simpler, XHTML is more structured. XHTML was designed to improve the extensibility and flexibility of HTML, making it easier to integrate HTML with other data formats like XML. Therefore, a decision must be made keeping in mind the advantages and disadvantages of each side.
3. How to migrate from XHTML to HTML?
Learning about the coding conventions of both formats is a must before attempting to migrate from one format to the other. Even after learning this, there are no fixed set of steps for doing so. However, if you want to attempt this conversion by hand, you can follow these steps:
- Use the lang attribute to specify an element’s language instead of the XHTML xml:lang attribute.
- Delete the XML namespace(xmlns=URI) from the code.
- Edit the declaration of the document type to HTML 4.01 from XHTML 1.0.
- Delete the XML declaration if it exists.
- Make sure that the MIME type of the document is fixed at text/html
- Change the XML empty-element syntax (br/> to br>) to an HTML style empty element.
In case you do not want to do so manually, software tools can do the trick too. One such popular tool is HTML Tidy, developed by members of W3C, which can clean up and convert both versions of the languages.
4. Is HTML case sensitive?
Generally speaking, HTML is not case-sensitive. However, when it comes to attributing values, it is case-sensitive. Names of tags and attributes are of course case insensitive. Additionally, entity names are case-sensitive.