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Extensible Markup Language (XML) Activity Statement. The Extensible Markup Language (XML) is a simple, flexible text format derived from SGML (ISO 8879). The W3C created and maintais the XML specification. The W3C is also the primary center for developing other cross-industry specifications that are based on XML. Some of these are done within the XML Activity, such as XML Query and XML Schema, and some (such as SVG) in other W3C areas. The XML Activity tries to keep a balance between maintaining stability and backwards compatibility, making improvements that help to encourage interoperability, and bringing new communities into the world of XML. Highlights since the previous W3C Advisory Committee meeting Low W3C staff resources in the XML Activity meant that much work was done without technical staff involvement.
Overall, XML has seen a resurgence in uptake because of the publishing industry. The XML Print and Page Layout Working Group (working on XSL-FO for formatting) was closed because of a lack of participation.
Balisage: The Markup Conference. Extensible Markup Language (XML) Nearby: XML Specifications and Translations of them. Introduction Extensible Markup Language (XML) is a simple, very flexible text format derived from SGML (ISO 8879). Originally designed to meet the challenges of large-scale electronic publishing, XML is also playing an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere. This page describes the work being done at W3C within the XML Activity, and how it is structured.
Work at W3C takes place in Working Groups. You can find and download formal technical specifications here, because we publish them. You will find links to W3C Recommendations, Proposed Recommendations, Working Drafts, conformance test suites and other documents on the pages for each Working Group. Please do not send us email asking us to help you learn a language or specification; there are plenty of resources online, and the people editing and developing the specifications are very busy. Working Groups XSLT Working Group Contact Note. XML Reserved Markup Characters. Has average rating 5 out of 10. Total 2 users rated. <<PreviousNext>> The open angle bracket (<) and ampersand (&) are reserved for markup. Element tags must began with the < character, and entities and character references in a xml document must began with the & character, which means that if you use any if these characters for any other purpose than mentioned here, it will generate an error.
When an xml parser encounters the <character, it assumes an element or other markup statement is about to start. If it does not find the characters it is expecting next, i.e. a xml name followed directly by a right angle bracket or a comment or a processing instruction, it generates an error. Similarly, when a xml parser encounters an & character, it assumes it has encountered an entity. Using predefined entities in place of <, >, & and " characters is called escaping a character. Examine the following lines of code to see if you can identify the legal and illegal uses of the < and & characters. XML Prohibited character literals. <<PreviousNext>> Introduction Following characters are prohibited in XML: & lt; & amp; & gt; & apos; & quot; Certain characters cause problems when used as element content or inside attribute values.
Specifically, the less-than character cannot appear either as a child of an element or inside an attribute value because it is interpreted as the start of an element. The same restrictions apply to the ampersand because it is used to indicate the starting of an entity reference. If the less-than or ampersand characters need to be encoded as element children or inside an attribute value, then a character entity must be used. A fifth character reference is also provided for the greater-than character .Although strictly speaking such characters seldom need to be “escaped,” many people prefer to “escape” them for consistency with the less-than character. Example of Built-in entity in element content: <IceCream> <name>Cherry Garcia</name> <manufacturer>Ben & Jerry</manufacturer> </IceCream> XML Proper nesting of elements. XML Proper nesting of elements has average rating 1 out of 10.
Total 1 users rated. <<PreviousNext>> In xml, elements can not stand alone in the document. All of the elements need to be contained within a hierarchy of elements that begins with the root element. So in a nutshell, if you have three elements in your xml document, the root element must contain the other two. The easiest way to understand this concept is to simply get into one valuable habit when marking up an xml document: when you create a start tag for an element, immediately create the end tag. <message> <header> <from>webmaster@w3resource.com</from> <to>webmaster@w3resource.com</to> <subject>On xml</subject> </header> <body> <message><header><from>webmaster@w3resource.com</from><to>webmaster@w3resource.com</to><subject>On xml</subject></header><body> Nesting of xml elements must be proper, in a well-formed xml document.
This markup would be wrong if the elements weren't nested properly The following will generate an error: XML Namespaces. XML Namespaces has average rating 9 out of 10. Total 3 users rated. <<PreviousNext>> Introduction Since XML allows designers to chose their own tag names, it is possible that two or more designers may chose the same tag names for some or all of their elements.
Syntax <prefix:localname xmlns:prefix='namespace URI'>children</prefix:localname/> This XML contains a list of tutorials for client side tools of web development: <? <? This XML contains a list of tutorials for server side tools of web development: <? <? If these two XML instances are put together, since both of them carry elements with tagname name, it will create a naming collision. <?
<? Namespaces themselves also have names. <? <? This is another example of using qualified elements using a default namespace declaration: <? <? Namespace declarations appear inside an element start and end tag and are used to map a namespace prefix. It is also possible to map a namespace name to no prefix using a default namespace declaration. Example of QNames: XML CDATA. <<PreviousNext>> Syntax CDATA sections can be used to “block escape” literal text when replacing prohibited characters with entity references is undesirable. CDATA sections can appear inside element content and allow < and & character literals to appear.
A CDATA section begins with the character sequence <! [CDATA[ and ends with the character sequence ]]>. Between the two character sequences, an XML processor ignores all markup characters such as <, >, and &. The only markup an XML pro-cessor recognizes inside a CDATA section is the closing character sequence ]>. Example of CDATA sections <sometext> <! <sometext><! For all CDATA,the character literals which are prohibited, are not characters which are not lterals and since they are not, it causes problems for exporting data in the form of other datasets like executing Processsing Instructions.
Example of Built-in entity in element content Use of the built-in entity ' inside attribute content. XML Parameter Entities. XML Parameter Entities has average rating 5 out of 10. Total 1 users rated. <<PreviousNext>> Parameter entities are used exclusively within DTDs. Parameter entities accomplish the same task as the other entities do, i.e. acting as a shortcut. Using parameter entities you can include element and attribute list declarations as groups and refer to them easily as single entities. Parameter entities distinguish themselves from other entities by the inclusion of one simple character. Notice that there is nothing else on either side of the percent sign. The xml declaration is part of the document prolog, as you will discover later, and not part of the document instance (the main body of the document that holds the data you are working with).
XML Attribute. <<PreviousNext>> Attribute value Any attribute value must consist of one of the following types of attributes available to an XML document. CDATA ENTITY Enumeration ID IDREF IDREFS NMTOKEN NMTOKENS NOTATION Attribute syntax <! For all CDATA, the character literals which are prohibited, are not characters which are not literals and since they are not, it causes problems for exporting data in the form of other datasets like executing Processing Instructions. Example of Built-in entity in attribute content: Use of the built-in entity ' inside attribute content Example of CDATA sections <sometext> <! <sometext><! For all CDATA, the character literals which are prohibited, are not characters which are not literals and since they are not, it causes problems for exporting data in the form of other data sets like executing Processing Instructions.
XML Quotation marks for attribute values Attribute values must be enclosed in quotation marks. These are correct use of quotes: Attribute and namespace. XML Entity. <<PreviousNext>> What is an Entity Before we read a definition, consider the following html code <html> <head> <title>XML Entity Example</title> </head> <body> <p>An xml tag starts with < and ends with ></p> </body> </html> <html><head><title>XML Entity Example</title></head><body><p>An xml tag starts with < and ends with ></p></body></html> Click on this link to open this in a browser. You can see an output like this : An xml tag starts with < and ends with > Now notice that greater than (>) and less than (<) signs are written as < and > in the html code above. Use of Entities in xml document Denoting special markup, such as the > and < tags.
Rules for using legal Entity Markup The entity must be declared in the DTD. Types of entities In general we have three types of entities: internal entities, external entities and parameter entities. Internal Entities These are entities that refer to entities whose definitions can be found entirely within a document's DTD. XML Internal Entities. XML Internal Entities has average rating 6 out of 10. Total 3 users rated. <<PreviousNext>> Internal Entities An internal entity is one that is defined locally within a DTD. To use an entity you insert an "entity reference" into your document.
If you've defined the entity "compname" to contain the name of your company, then you can use it with the following entity reference "&compname;". The text that is inserted by an entity reference is called the "replacement text". Entity declaration Entities must be declared before they can be used. All entities are declared with the "ENTITY" declaration. Declaring Internal Entities An internal entity declaration has the following form: You can use either double or single quotes to delimit the replacement text. Predefined Internal Entities There are five internal entities which are predefined in internal entities. Here is a table containing predefined entities and their replacement text: XML External Entities.
External Entities External entities offer a mechanism for dividing your document up into logical chunks. Rather than authoring a monolithic document, a book with 10 chapters for example, you can store each chapter in a separate file and use external entities to "source in" the 10 chapters. Because external entities in different documents can refer to the same files on your file system, external entities provide an opportunity to implement reuse. Reuse of small, discrete components (figures, legal boilerplate, warning messages) is fairly easy to manage. Implementing reuse on a large scale requires an entity management system which XML, by itself, does not provide.
A few notes about external entities External entities do not have to consist of a single element; you can make a sequence of three paragraphs, or even a bunch of character data with embedded inline markup into an external entity. Declaring External Entities External entity declarations come in two forms. <! <! XML Processing instructions (PI) XML Elements. XML Elements has average rating 9 out of 10. Total 1 users rated. <<PreviousNext>> Introduction Elements are the basic building blocks of an XML document. Syntax of an XML Element <name_of_the_element>text</name_of_the_element> Following are the basic characteristics of XML Elements Most of the data contained by an XML document, is enclosed within XML Elements.
<html> <body> <head> <title>w3resource-xml</title> </head> <body> <p><b>This is w3resource.com. <html><body><head><title>w3resource-xml</title></head><body><p><b>This is w3resource.com. example xml file: <xml> <tutorial>w3resource <one>html</one> <two>xml <subtopic1>Learning xml</subtopic1> <subtopic2>Learning DTD</subtopic2> <subtopic3>Learning XSLT</subtopic3> <subtopic4>Learning xpath</subtopic4> </two> <three>css</three> <four>javascript</four> <five>ajax</five> <six>php</six> <seven>mysql</seven> <eight>svg</eight> </tutorial> </xml> Children of an element reside with the open and close tags of their parents. <? <? <? <? <? <? XML Comments, Whitespaces. XML Tutorial. XML Tutorial has average rating 8 out of 10.
Total 39 users rated. <<PreviousNext>> What is xml? The following points will help you to get a basic understanding of what xml is: XML stands for Extensible Markup Language. A markup language uses a set of additional items called markups to create a document of hierarchical structure. Example of an xml document: <? <? Now if you copy and save this code above as an .xml file and then double-click it to execute and check the output, it will show you something very readable, all in text format.
Now let's add this style-sheet to the xml document: <? <? Advantages of xml Since xml supports UNICODE, all most all the human readable written languages can be communicated using xml. XML Document Several times, through this tutorial, you are going to encounter the phrase 'XML Document'. Difference between xml and html Here are some differences between xml and html: Html tags are predefined, where as xml tags are not. Example : HTML file Example : XML file. Well Formed XML. <<PreviousNext>> Introduction An XML document is called well formed if it satisfies certain rules, specified by The W3C. These rules are: An well formed XML document must have a corresponding end tag for all of its start tags.
Nesting of elements within each other in an XML document must be proper. Example of a Valid XML document. <? <? Example of an invalid XML <? <? To check whether an XML document is well-formed or not, you have to use an XML parser. An XML parser is a Software Application, which introspects an XML document and stores the resulting output in memory.
Well formed XML is an XML document which follows some rules specified by W3C. Uses of xml. XML declarations. XMLand HTML.