Another learning XML~~~

XML

Introduction to XML.

XML stands for Extensible Markup Language. XML was designed to describe data and focus on what data is. It is a markup language much like HTML.

Description of XML.

XML is a software-and hardware-independent tool for carrying information

Difference between XML and HTML.

XML is not a replacement for HTML. These are some of the differences between them.

	XML	HTML
Goal	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
Tags	-XML language has no predefined tags - XML allows the author to define his own tags and his own document structure	- The tags used in HTML (and the structure of HTML) are predefined -HTML documents can only use tags defined in the HTML standard (like <p>, <h1>, etc.)
Closing Tag	All XML Elements Must Have a Closing Tag	In HTML, you will often see elements that don't have a closing tag: –<p>This is a paragraph<p>This is another paragraph
Properly nested	In XML, all elements must be properly nested within each other: <b><i>This text is bold and italic</i></b>	In HTML, you might see improperly nested elements: <b><i>This text is bold and italic</b></i>
White-space	With XML, the white-space in a document is not truncated	HTML truncates multiple white-space characters to one single white-space:

Well-formed XML Documents.

Well formed XML documents must have a correct syntax, which are:

·        XML documents must have a root element

·        XML elements must have a closing tag

·        XML tags are case sensitive

·        XML elements must be properly nested

·        XML attribute values must be quoted

As we know, XML documents must contain a root element. This element is "the parent" of all other elements. The elements in an XML document form a document tree. The tree starts at the root and branches to the lowest level of the tree.

For example:

Then form a document tree (one book of the document above):

Last but not least, XML is nothing special. It is just plain text. Software that can handle plain text can also handle XML.

www.w3schools.com/xml/xml_whatis.asp