How XML works?

Answer 1

Explain how can xml used in web page design to carry data? Using XML to exchange information offers many benefits, including the following: * Uses human, not computer, language. XML is readable (and understandable, even by novices) and no more difficult to code than HTML. * Completely compatible with Java and 100% portable. Any application that can process XML (on any platform) can use your information. * Extendable. Create your own tags (or use tags created by others) that use the native language of your domain, have the attributes you need, and make sense to you and your users. The following example illustrates, in a simplified way, the readability and extensibility of XML: HTML example XML example

State

City

Name

Johnson

Population

5000

City

Name

Pineville

Population

60000

City

Name

Lake Bell

Population

20

Johnson 5000 Pineville 60000 Lake Bell 20 HTML tag names reveal nothing about the meaning of their content. The example above uses an HTML definition list, but the problems inherent in using HTML would occur if the data were contained in a table or some other kind of HTML tags: For example: * Many the HTML tags are acronyms, so they are not as readable as common language. * HTML tags represent data (in this above example, city names and populations) as items to display, for example, as definitions in a list or cells in a table. This makes it difficult to manipulate the data or or exchange it between applications. The XML tag names are readable and convey the meaning of the data. Each XML tag immediately precedes the associated data, helping to make the information structure easily discerned by both humans and computers. The data structure follows a noticeable and useful pattern, making it easy to manipulate and exchange the data. XML has a variety of uses, including: * Web publishing: XML allows you to create interactive pages, allows the customer to customize those pages, and makes creating e-commerce applications more intuitive. With XML, you store the data once and then render that content for different viewers or devices based on style sheet processing using an XSL/XSLT processor. * Web searching and automating Web tasks: XML defines the type of information contained in a document, making it easier to return useful results when searching the Web: For example, using HTML to search for books authored by Tom Wolf is likely to return instances of the term 'wolf' outside of the context of author. Using XML restricts the search to the proper context (say, the information contained in the tag) and returns only the desired type of information. Using XML, Web agents and robots (programs that automate Web searches or other tasks) will be more efficient and produce more useful results. * General applications: XML provides a standard method to access information, making it easier for applications and devices of all kinds to use, store, transmit, and display data. * E-business applications: XML implementations make electronic data interchange (EDI) more accessible for information interchange, business-to-business transactions, and business-to-consumer transactions. * Metadata applications: XML makes is easier to express metadata (Unified Modeling Language design models or user interface properties, for example) in a portable, reusable format. * Pervasive computing: XML provides portable and structured information types for display on pervasive (wireless) computing devices such as PDAs, cellular phones, and others. For example, WML (Wireless Markup Language) and VoiceXML are currently evolving standards for describing visual and speech-driven wireless device interfaces.

Answer 2

XML is a markup language, one that supplies meta data, data about the data contained within the XML elements and attributes. As such, and in its most primitive application, XML can be used to store arbitrary data, and can be used to communicate this data across machine boundaries and networks.

However, many specific applications of XML are based on an agreed markup and standard tools that rely on this agreed markup. Schema is an XML language that allows defining rules, limitations and relations between data. XSLT is a XML programming language designed for machine-driven language-to-language translation. Numerous other XML based languages and technologies exist, such as XPath, XQuery, XLink, or declarative programming languages such as Adobe's MXML or part of Microsoft's Metro.