1. What is XML?
XML is the Extensible Markup Language. It improves the functionality of the Web by letting you identify your information in a more accurate, flexible, and adaptable way. It is extensible because it is not a fixed format like HTML (which is a single, predefined markup language). Instead, XML is actually a meta language—a language for describing other languages—which lets you design your own markup languages for limitless different types of documents. XML can do this because it’s written in SGML, the international standard meta language for text document markup (ISO 8879).
2. What is a markup language?
A markup language is a set of words and symbols for describing the identity of pieces of a document (for example ‘this is a paragraph’, ‘this is a heading’, ‘this is a list’, ‘this is the caption of this figure’, etc). Programs can use this with a style sheet to create output for screen, print, audio, video, Braille, etc. Some markup languages (eg those used in word processors) only describe appearances (’this is italics’, ‘this is bold’), but this method can only be used for display, and is not normally re-usable for anything else.
3. Why is XML such an important development?
It removes two constraints which were holding back Web developments: 1. dependence on a single, inflexible document type (HTML) which was being much abused for tasks it was never designed for;
2. the complexity of full SGML, whose syntax allows many powerful but hard-to-program options. XML allows the flexible development of user-defined document types. It provides a robust, non-proprietary, persistent, and verifiable file format for the storage and transmission of text and data both on and off the Web; and it removes the more complex options of SGML, making it easier to program for.
XML is the Extensible Markup Language. It improves the functionality of the Web by letting you identify your information in a more accurate, flexible, and adaptable way. It is extensible because it is not a fixed format like HTML (which is a single, predefined markup language). Instead, XML is actually a meta language—a language for describing other languages—which lets you design your own markup languages for limitless different types of documents. XML can do this because it’s written in SGML, the international standard meta language for text document markup (ISO 8879).
2. What is a markup language?
A markup language is a set of words and symbols for describing the identity of pieces of a document (for example ‘this is a paragraph’, ‘this is a heading’, ‘this is a list’, ‘this is the caption of this figure’, etc). Programs can use this with a style sheet to create output for screen, print, audio, video, Braille, etc. Some markup languages (eg those used in word processors) only describe appearances (’this is italics’, ‘this is bold’), but this method can only be used for display, and is not normally re-usable for anything else.
3. Why is XML such an important development?
It removes two constraints which were holding back Web developments: 1. dependence on a single, inflexible document type (HTML) which was being much abused for tasks it was never designed for;
2. the complexity of full SGML, whose syntax allows many powerful but hard-to-program options. XML allows the flexible development of user-defined document types. It provides a robust, non-proprietary, persistent, and verifiable file format for the storage and transmission of text and data both on and off the Web; and it removes the more complex options of SGML, making it easier to program for.
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