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This module is part of a collection dedicated to learning XML.

Table of contents

Preface

General

This module is part of a collection dedicated to learning XML.

Viewing tip

I recommend that you open another copy of this document in a separate browser window and use the following links to easily find and view the figures while youare reading about them.

Figures

Supplemental material

I recommend that you also study the other lessons in my extensive collection of online programmingtutorials. You will find a consolidated index at www.DickBaldwin.com .

A brief introduction to XML

The name XML derives from e X tensible M arkup L anguage. According to Wikipedia,

"A markup language is a system for annotating text in a way which is syntactically distinguishable from that text."

In other words, when text has been annotated or marked up, the annotations can be easily distinguished from the original text. For example, if you turn in a termpaper and the professor annotates it with a red pencil, you can easily distinguish her annotations from your original text. However, XML doesn't usecolor to annotate text. Instead, XML uses specially formatted text to annotate text.

Structured documents

XML gives us a way to create and maintain structured documents in plain text that can be rendered in a variety of different ways. For example, before Iupload this document to the Connexions website for publishing, I will convert into CNXML , which is one of the many flavors of XML. Once the document is on the website inthat format, programs on the website have the ability to render it in the form of a web page (which you are probably reading right now) or in the form of a PDF document, which you can download andprint if you choose to do so.

There is a lot of jargon involved in XML. One of my objectives will be to explain the jargon.

What do I mean by a "structured document?"

I will answer this question by providing an example. A book is a structured document. In its simplest form, a book may be composed of chapters. The chaptersmay be composed of sections. The sections may contain illustrations and tables. The tables are composed of rows and columns. Thus, it would be possible to drawa picture that illustrates the structure of a book.

What do I mean by "plain text?"

Characters such as the letters of the alphabet and punctuation marks are represented in the computer by numeric values, similar to a simple substitutioncode that a child might devise. For example in one popular encoding scheme (ASCII), the upper-case version of the character "A" is represented by the value65, a "B" is represented by the value 66, a "C" is represented by 67, etc.

Different encoding schemes

The actual correspondence between the characters and the specific numeric values representing the characters has been described by several differentencoding schemes over the years. One of the most common and enduring schemes is a scheme that was devised a number of years ago by an organization known as theAmerican Standards Committee on Information Interchange. This encoding scheme is commonly known as the ASCII code.

Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir 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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