About the differences between HTML, XHTML, CSS, and XML

1.HTML (Hyper Text mark-up Language)

HTML (Hyper text mark-up Language), which is a Hypertext markup language or hyperlinked language, is a sign language designed for "Web page creation and other information that can be seen in a Web browser," and is the primary language that constitutes a Web document.

The purpose of the HTML language is to make it easy to connect text or graphics stored on one computer with text or graphics from another computer to form an organic whole, regardless of whether the specific information is on the current computer or on other computers in the network. We just use the mouse to pick an icon in a document, and the Internet immediately goes to the content associated with that icon, which may be stored on another computer in the network.

HTML text is a descriptive text made up of HTML commands that describe text, graphics, animations, sounds, tables, links, and so on. The structure of the HTML consists of the head (head) and the body (body), where the head describes the information required by the browser, while the body contains the specific content to be described.
Regarding the HTM, there is actually no essential difference between the HTM and HTML, just to satisfy the DOS to recognize only three-bit filenames, because some older systems (Win32) do not recognize the four-bit file name, so some Web server requires index.html the last L must be removed. (because HTML is not recognized, only the HTM is recognized). MSIE can automatically identify and open these files, but the page address must be written in full correspondence, that is to say index.htm and index.html is two different files, corresponding to different addresses.

2.XHTML (extensible hypertext Markup Language)

More advanced and difficult to understand technology XHTML?
Simply put: X is scary, but XHTML is a rigorous and accurate HTML. If HTML is Chinese, then XHTML is Standard Mandarin. For friends who are just beginning to learn web design, it is the best choice to learn XHTML directly.
The complex point is that XHTML is an "upgrade specification" for HTML products, where "X" stands for extensibility and is the abbreviation for the word "extensible". In fact, it also belongs to the HTML family, compared to previous versions of HTML, it has more stringent writing standards, better cross-platform capabilities. Because of some needs, XHTML gives CSS the ability to implement some of the previous versions of HTML, which means you will need to learn two techniques. But this is really the trend of the future development of the Web. X stands for "expandable". Edit the version history of the HTML standard for this paragraph

1) Development history of HTML and XHTML

HTML 1.0 – published (not standard) for the work of the Internet Engineering Working Group (IETF), June 1993.
HTML 2.0--released in November 1995 as RFC 1866, declared obsolete after RFC 2854 was released in June 2000
HTML 3.2--January 14, 1996, the recommended standard
HTML 4.0--December 18, 1997, the recommended standard
HTML 4.01 (minor improvements)--December 24, 1999, the recommended standard
ISO/IEC 15445:2000 ("ISO HTML")-released on May 15, 2000, based on strict HTML 4.01 syntax, is the standard of the International Organization for Standardization and the IEC
The XHTML 1.0--, published on January 26, 2000, was the recommended standard for the publication, which was later revised on August 1, 2002.
XHTML 1.1-released on May 31, 2001

3.XML (extensible Markup Language)

Website: www.w3.org/TR/WD-xml

1) The original sin of being aware of HTML:
-Does not solve all the problem of interpreting data-such as audio-visual files or chemical formulas, musical symbols and other types of content;
-Performance issues-need to download the entire document, in order to start the search for the file action;
-Scalability, elasticity, legibility are poor;
To solve these problems, experts use SGML to streamline production, and in accordance with the development experience of HTML, produce a set of strict rules, but simple description data language: XML. XML is a more neutral way to let the consumer decide how to digest and present the information provided from the server. The purpose of XML is to provide a mechanism by which information can be accurately described to compensate for the too-expressive nature of HTML.

2) What is XML?

XML (extensible Markup Language) extends markup Language (starting in 1998), which, like HTML, is based on SGML (standard common language). XML is a cross-platform, content-dependent technology in an Internet environment, and is a powerful tool for the current processing of structured document information. XML is a simple data storage language that uses a series of simple tags to describe data that can be built in a convenient way, although XML occupies more space than binary data, but XML is extremely simple and easy to master and use.
The simplicity of XML makes it easy to read and write data in any application, which makes XML quickly the only common language for data exchange, although different applications support other data interchange formats, but soon they will support XML, which means that programs can be easier with Windows, Mac OS, Linux and other platforms generated by the combination of information, and then can easily load XML data into the program and analyze him, and output the results in XML format.
Unlike databases such as access,oracle and SQL Server, the database provides more powerful data storage and analysis capabilities, such as data indexing, sorting, lookups, correlation consistency, and so on, where XML is just the presentation of data. In fact, the biggest difference between XML and other data representations is that he is extremely simple. This is a seemingly trivial advantage, but it is this that makes XML different.

4. SHTML

If a sentence to explain is: sHTML is not HTML, but a server api,shtml is the server dynamically produced HTML.
Although both are hypertext formats, shtml is a file for SSI technology. That is, the server Side Include--ssi contains instructions. If the Web server has SSI capabilities (most (especially UNIX-based platforms), Web servers such as Netscape Enterprise Server support SSI commands). The shtml file will be specially entertained. Sweep the shtml file first to see no special SSI instructions now. The SSI directive is interpreted according to the Web server setting rules. After the explanation, with the general HTML dropped to the client.
sHTML uses the HTML file extension of SSI (server Side include), SSI (server Side include), often referred to as "server-side embedding" or "server-side containment", which is an ASP-like server-based Web authoring technology.

5. CSS (cascading style Sheets) cascading style sheet

What is CSS? You may be anxious to know the answer. But the empty text description is not very meaningful, let us first a little perceptual experience it. Look at this. html file with no CSS added: http://www.csszengarden.com/zengarden-sample.html
is an ordinary Web page. However, by adding CSS rules to this file, we can get a very beautiful page: http://www.csszengarden.com/
This is not all, do not change the HTML, just by adding different CSS rules, we can get a variety of different styles of Web pages:
Http://www.csszengarden.com/?cssfile=/208/208.css&page=0

OK, let's answer the question about CSS. What is cascading style Sheets (cascading style sheets)
* CSS is the abbreviation for cascading style Sheets (cascading style sheets).
* The CSS language is a markup language that does not need to be compiled and can be executed directly by the browser (which belongs to the browser-interpreted language).
* CSS is responsible for the performance of Web content (XHTML) in standard web design.
* CSS file can also be said to be a text file, it contains some CSS tags, css files must use CSS as the filename suffix.
* Can reduce our workload by simply changing the css file, changing the overall form of the page, so she is a required course for every web designer.
* CSS is generated and maintained by the CSS Workgroup

About the differences between HTML, XHTML, CSS, and XML