What format is xml?

xml is a plain text format file. xml refers to extensible markup language, a subset of standard universal markup language. It is a markup language used to mark electronic documents to make them structural; XML files generally refer to files with extensible markup language code written in them.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

XML files generally refer to files with extensible markup language written in them.

xml generally refers to Extensible Markup Language, a subset of Standard Universal Markup Language. It is a markup language used to mark electronic documents to make them structural.

The XML file format is a plain text format, similar to HTML in many ways. XML consists of XML elements. Each XML element includes a start tag, an end tag and the content between the two tags. For example, XML elements can be marked as price, order number or name. Markup is a description of the document storage format and logical structure. Formally, markup may include comments, quotes, character data segments, start tags, end tags, empty elements, document type declarations (DTD), and prologues.

The simplicity of XML makes it easy to read/write data in any application, which quickly made XML the only common language for data exchange. Although different application software also supported other data exchange formats, it was not long before they All will support XML, which means that programs can more easily integrate with information generated under Windows, Mac OS, Linux and other platforms. It can then easily load XML data into the program and analyze it, and output the results in XML format. .

XML has the following characteristics:

(1) XML can separate data from HTML. That is, the data can be stored in the XML document outside of the HTML file. This allows developers to focus on using HTML to display and layout the data, and ensures that when the data is changed, the HTML file will not also need to be changed, thus making it easier to maintain the page. . XML can also store data in HTML pages in the form of "data islands", so developers can still focus on formatting and displaying data using HTML.

(2) XML can be used to exchange data. Data can be exchanged between incompatible systems based on XML. Data stored in computer systems and database systems comes in many forms. For developers, the most time-consuming task is to exchange data between systems spread across the network. Converting data to XML format storage will greatly reduce the complexity of exchanging data and also enable the data to be read by different programs.

(3) XML can be used in B2B. For example, in exchanging financial information on the network, XML is currently becoming the main language used to exchange information between business systems spread across the network, and many B2B-related applications based entirely on XML are being developed.

(4) Data can be shared using XML. XML data is stored in plain text format, which makes XML easier to read, easier to record, easier to debug, and easier to share data between different systems and different programs.

(5) XML can make full use of data. XML is independent of software, hardware and applications, and data can be used by more users and devices, not just browsers based on HTML standards. Other clients and applications can process XML documents as data sources, and just like a database, XML data can be processed by a variety of "readers."

(6) XML can be used to create new languages. For example, WAP and WML languages ​​are both developed from XML. WML (Wireless Markup Language) is a tool used to identify Internet programs running on handheld devices (such as mobile phones). It adopts the XML standard.

In short, XML uses a simple and flexible standard format to provide an effective means for describing data and exchanging data for Web-based applications. However, XML is not intended to replace HTML. HTML focuses on describing how to display files in a browser, while XML is similar to SGML in that it focuses on describing how to represent data in a structured manner.

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