EXTENSIBLE MARKUP LANGUAGE
We are further detail about XML on:-
XML(Extensible Markup Language) was designed to describe data and focus what data is. It is
a markup language much like HTML but the tags are not predefined. It uses a DTD or an XML
schema to describe the data with a DTD or XML Schema is designed to self-descriptive.
The Difference Between XML and HTML..!!
lXML is not a replacement for HTML
lXML and HTML were designed with different goals:
–XML was designed to transport and store data, with focus on what data is
–HTML was designed to display data, with focus on how data looks
lHTML is about displaying information, while XML is about carrying information
XML Does not DO Anything because..
lXML was created to structure, store, and transport information
The following example is a note to Tove from Jani, stored as XML:
<body>Don't forget me this weekend!</body>
<body>Don't forget me this weekend!</body>
XML is Just Plain Text
XML is nothing special because It is just plain text. Any software that can handle plain text can
also handle XML. However, XML-aware applications can handle the XML tags specially. The
functional meaning of the tags depends on the nature of the application.
With XML You Invent Your Own Tags
The tags in the example above (like <to> and <from>) are not defined in any XML standard.
That is because the XML language has no predefined tags. These tags are "invented" by the
author of the XML document.The tags used in HTML (and the structure of HTML) are
predefined and HTML documents can only use tags defined in the HTML standard (like <p>,
<h1>, etc.) but XML allows the author to define his own tags and his own document structure.
XML is Not a Replacement for HTML but
lXML is a complement to HTML
–In most web applications, XML is used to transport data, while HTML is used to format and display the data
lXML is a software- and hardware-independent tool for carrying information
XML is actually everywhere. We have been participating in XML development since its
creation. It has been amazing to see how quickly the XML standard has developed, and how
quickly a large number of software vendors have adopted the standard. XML is now as
important for the Web as HTML was to the foundation of the Web. It is the most common tool
for data transmissions between all sorts of applications, and is becoming more and more
popular in the area of storing and describing information.
How Can XML be Used?
XML is used in many aspects of web development, often to simplify data storage and sharing.
THE BENEFITS OF XML
1. XML Separates Data from HTML
lIf you need to display dynamic data in your HTML document, it will take a lot of work to edit the HTML each time the data changes
lWith XML, data can be stored in separate XML files
lThis way you can concentrate on using HTML for layout and display, and be sure that changes in the underlying data will not require any changes to the HTML
2. XML Simplifies Data Sharing
lWith XML, data can easily be exchanged between incompatible systems
lOne of the most time-consuming challenges for developers is to exchange data between incompatible systems over the Internet
lExchanging data as XML greatly reduces this complexity, since the data can be read by different incompatible applications
3. XML Simplifies Platform Changes
lUpgrading to new systems (hardware or software platforms), is always very time consuming
lLarge amounts of data must be converted and incompatible data is often lost
lXML data is stored in text format
lThis makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data
4. XML Makes Your Data More Available
lSince XML is independent of hardware, software and application, XML can make your data more available and useful
lDifferent applications can access your data, not only in HTML pages, but also from XML data sources
lWith XML, your data can be available to all kinds of "reading machines" (Handheld computers, voice machines, news feeds, etc), and make it more available for blind people, or people with other disabilities
5. XML is Used to Create New Internet Languages
lA lot of new Internet languages are created with XML
lHere are some examples:
–XHTML the latest version of HTML
–WSDL for describing available web services
–WAP and WML as markup languages for handheld devices
–RSS languages for news feeds
–RDF and OWL for describing resources and ontology
–SMIL for describing multimedia for the web