XML

Computers use a special way to share facts. It is called XML. This way uses labels to sort things. These labels are called tags. Tags help computers read data. They also help people read it. One tag can start a piece of info. Another tag ends it. This keeps everything in order. It is like a map for data. It works well on the web. It helps different machines talk to each other.

Computers need a way to share facts. They use a system called XML. XML stands for Extensible Markup Language. It is a way to store and send data. It uses rules to organize information. These rules make the data easy for people to read. They also make it easy for machines to read.

XML uses labels called tags. These tags mark the parts of a document. A tag usually starts with a < symbol. It ends with a > symbol. Some tags have extra info called attributes. An attribute is a name and a value. For example, a tag might name a file. This helps the computer know what the data is.

XML is like a common language. It helps two different systems talk to each other. Many things on the web use XML. It helps make files for maps or weather data. It also helps with office documents. XML can use many different human languages. This is thanks to a system called Unicode. It lets computers show almost any character from around the world.

XML is a special way to store and send data. It stands for Extensible Markup Language. This tool helps different computer systems talk to each other. It works like a common language for machines. This process is called serialization. It means storing and moving data so it can be rebuilt later. XML is very important for the internet. It makes sure information stays organized and clear. It is easy for people to read. It is also easy for computers to read. This makes it a great tool for the web.

XML uses labels called tags to organize information. A tag is a piece of markup. It usually starts with a < symbol and ends with a > symbol. These tags tell the computer what the data is. For example, an element might look like <greeting>Hello!</greeting>. The word "Hello!" is the content. You can also use attributes to add extra details. An attribute is a name and a value pair inside a tag. One example is <img src="photo.jpg">. Here, "src" is the name and "photo.jpg" is the value.

People have worked on these rules for a long time. The World Wide Web Consortium created the XML 1.0 Specification in 1998. These rules are free and open for everyone to use. There are also newer versions like XML 1.1. These standards help keep everything consistent. Many programmers also make tools called APIs. These tools help computers process XML data more easily.

There are many important rules for using XML. A document must follow certain syntax rules to be "well-formed." If it also follows a specific schema, it is called "valid." A schema is a set of rules that defines the data. XML can also use Unicode to show many different languages. This includes characters from Chinese, Armenian, and Cyrillic. It even handles special symbols through a process called escaping. For instance, the symbol < is written as &lt; so it does not confuse the computer.

XML is used in many parts of our daily lives. It helps power many document formats. Some examples include RSS, SVG, and Office Open XML. It is even used in science for weather data. Meteorologists use it for operational weather information. It also helps with web services and communication protocols like SOAP. You might even see it working behind the scenes when you use AJAX on a website.

Extensible Markup Language, or XML, is a specialized markup language and file format. It is used for the storage, transmission, and reconstruction of data. This process is known as serialization. Serialization allows different, separate computer systems to exchange information by agreeing on a single file format. Because of this, XML acts like a lingua franca, which is a common language used by many different groups. XML is designed to be both human-readable and machine-readable. It emphasizes simplicity, generality, and usability across the entire Internet.

To organize information, XML uses a system of markup and content. Markup consists of specific strings of characters that follow syntactic rules. These strings usually begin with a less-than sign < and end with a greater-than sign >. They can also begin with an ampersand & and end with a semicolon ;. The information located between these markup markers is called content. An XML processor, often called a parser, analyzes this markup. It then passes the structured information to an application for use.

There are several specific types of markup constructs within an XML document. The first is an element, which is a logical component of a document. An element starts with a start-tag and ends with a matching end-tag. The text inside is the element's content, which may include child elements. For example, <greeting>Hello, world!</greeting> shows a greeting element. The second type is an attribute, which is a name-value pair located inside a tag. In the tag <img src="madonna.jpg" alt="Madonna" />, "src" and "alt" are the attribute names. Their values are "madonna.jpg" and "Madonna."

XML documents must follow strict rules to be used correctly. A document that follows the basic syntax rules is described as "well-formed." If a document also adheres to a specific XML schema, it is called "valid." An XML schema, or XSD, provides the necessary metadata to interpret and validate the data. This schema acts as a set of rules for the document structure. Furthermore, the IETF RFC 7303 provides rules for constructing media types for XML messages. These include application/xml, application/xml-external-parsed-entity, and application/xml-dtd.

History shows that XML has been a standardized tool for many years. The World Wide Web Consortium released the XML 1.0 Specification in 1998. These specifications are free, open standards available to everyone. There is also an XML 1.1 version that extends certain capabilities. To handle various human languages, XML uses the Unicode character set. This allows the language to support many different scripts, such as Chinese, Armenian, and Cyrillic. XML even includes mechanisms to identify the specific encoding being used, such as UTF-8 or UTF-16.

Because some characters can cause errors, XML uses a process called escaping. Certain characters, like < and &, are used for syntax and cannot appear directly in content. To include them, users use predefined entities. For example, &lt; represents <, and &amp; represents &. If a user needs to include a character that is not on their keyboard, they can use a numeric character reference. For instance, the Chinese character "中" can be written as &#20013;. This ensures the data remains accurate during transmission.

XML is used extensively across many different industries and technologies. It serves as the base language for communication protocols like SOAP and XMPP. It is also a message exchange format used in AJAX programming. Many document formats rely on XML syntax, including RSS, Atom, SVG, and XHTML. In the business world, standards like Health Level 7 and the OpenTravel Alliance are based on XML. Even in science, XML is used to represent operational meteorology information through IWXXM standards. It is a fundamental tool for modern digital communication.