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Created using a WYSIWYG XHTML editor

I originally created the document as an XHTML document using a WYSIWYG XHTML editor that behaves muchlike a word processor. (If you don't know what WYSIWYG means, Google it.) Of course, the document has since undergone quite a lot of editing so the finalXHTML version probably doesn't match the XHTML code in Listing 3.

Transform to CNXML

Later on, I used a Java program of my own design to transform the final XHTML document into anotherflavor of XML known as CNXML for publishing on the Connexions website.

That illustrates another characteristic of XML. Because the formats of certain flavors of XML documentsare well defined, it is often practical to transform them from one flavor to another flavor.

That makes it possible for me to create the document using a program that is very similar to a word processorand then transform the output of that program into a fairly cryptic format that satisfies the publishing requirements of the website.

Your browser is rendering the document

When you accessed the document from the Connexions website, it was transformed back into an XHTML document and sent to yourcomputer.

As you can see in Listing 3, viewing raw XHTML isn't very enjoyable. Fortunately, your browser isacting as a rendering engine to render the raw XHTML text into a much more pleasing presentation format.

Back to the book example

A book that is created and maintained as an XML document could be rendered in a variety of different ways. Whichever way it is rendered, however, it wouldprobably be useful to separate and number the chapters. Therefore, the value of the number attribute could be used by the rendering engine to present the chapter number for a specific rendering.

In some renderings, the number might appear on an otherwise blank page that begins a new chapter. In a different rendering, the chapter number might appearin the upper right or left-hand corner of each page.

Tell me again, what is an element?

As I explained earlier, an element usually consists of a start tag (with optional attributes and namespace information) , an end tag , and the content sandwiched in between as shown earlier in Listing 2.

Elements can be nested

Elements can be nested inside other elements as shown in Listing 4.

Listing 4 . Nested elements.
<book><chapter number="1">Content for Chapter 1</chapter><chapter number="2">Content for Chapter 2</chapter></book>

In Listing 4, two chapter elements are nested inside a book element.

Why does XML use elements?

It is probably fair to say that the element constitutes the fundamental unit of information in an XML document. For example, the element defines the type ofinformation, such as chapter in our book example.

Sandwiched in between the start tag and the end tag of an element, we find the raw information (content) that the XML document is designed to convey. For a text document, you are likely to find a lot of content between the tags. Forexample, in Listing 3, there are several lines of text between the paragraph tags identified by the p and the /p enclosed in angle brackets.

Once again, what is content?

Of the four terms mentioned earlier, (tags, elements, content, and attributes) , content is the easy one. Content is sandwiched in between the start tag and the end tag of an element. Usually the content of the elements containsthe information that the XML document is designed to convey. In other words, this is where we put the information for which the document was created. Thetags and attributes are there to create the structure.

For example, if the XML document is being used for the creation and maintenance of material for a newspaper, the content constitutes the news. Ifthe XML document is being used for the creation and maintenance of a Java programming textbook, the content contains the information about Javaprogramming that we want to convey to the student.

Why do we need structure?

One of the primary objectives of XML is to separate content from presentation. If we insert the raw material as content into a structure definedby the tags, elements, and attributes, then that raw material can be presented in a variety of ways.


This section contains a variety of miscellaneous materials.

Housekeeping material
  • Module name: XML - Tags, Elements, Content, and Attributes
  • File: FlexXhtml0082.htm
  • Revised: 12/02/14

Financial : Although the Connexions site makes it possible for you to download aPDF file for this module at no charge, and also makes it possiblefor you to purchase a pre-printed version of the PDF file, you should be aware that some of the HTML elements in this module maynot translate well into PDF.

I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version ofthe module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale onAmazon.com showing me as the author. I neither receive compensation for those sales nor do I know who does receive compensation. If youpurchase such a book, please be aware that it is a copy of a module that is freely available on cnx.org and that it was made andpublished without my prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.


Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
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Source:  OpenStax, Introduction to xml. OpenStax CNX. Dec 02, 2014 Download for free at https://legacy.cnx.org/content/col11207/1.18
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