XML tutorial WEB page tool Language XML definition

XML is a simplified SGML, which combines the rich functions of SGML with the ease of use of HTML into the use of Web. XML retains the scalability of SGML, which makes XML basically different from HTML. XML is much more powerful than HTML. it is no longer a fixed tag, but promises

XML is a simplified SGML, which combines the rich functions of SGML with the ease of use of HTML into the use of Web. XML retains the scalability of SGML, which makes XML basically different from HTML. XML is much more powerful than HTML. it is no longer a fixed tag, but promises to define unlimited tags to describe the materials in the document and promise nested information structures. HTML is only a common method for displaying Web data, while XML provides a common method for directly processing Web data. HTML focuses on the web page display pattern, while XML focuses on the web page content.

XML contains the extended pattern Language XSL (Extensible Style Language) and extended link Language XLL (Extensible Linking Language ).

XSL is a language used to translate XML data into HTML or other patterns. XSL provides a stacked page CSS function that allows developers to create a Web page with an expression layer structure, which is different from the XML data structure. XSL can also structure stacked pages with HTML. XSL can indicate an unlimited number of tags, which make Web pages more colorful, such as dynamic text and horse-running text. In addition, XSL also processes multi-country text, dual-byte Chinese character display, and various grid processing methods.

XLL is the link language of XML. it is similar to HTML links, but it is more powerful. XLL supports scalable and multi-direction connections. It breaks through the most simple link restrictions in the concept of HTML supporting only super text, and supports domain names, bidirectional links, loops, and aggregation links of multiple sources independent of addresses. XLL links can be specified and managed based on user requests without document restrictions.

To make XML easier to learn and use, XML simplifies the functionality of *** SGML. Just as some 100,000 Chinese characters are commonly used only eight thousand, the common part of SGML accounts for only 20%, and XML discards the not commonly used part of SGML, which is reduced by 80%. In this way, the XML syntax clarifies that the book has only 30 pages, while SGML has 500 pages.

The ease of use is also taken into account in XML Design. the ease of use comes from two aspects: On the one hand, it is convenient for users to write Web pages, and on the other hand, it is not difficult for design staff to implement XML browsers.

In short, XML uses a simple and organic scale pattern, which provides an effective means to describe data and exchange data for the use of Web. HTML describes general methods for displaying global data, while XML provides a general method for directly processing global data.