- Sams Teach Yourself XML in 21 Days, Third Edition
- Table of Contents
- About the Author
- Acknowledgments
- We Want to Hear from You!
- Introduction
- Part I: At a Glance
- Day 1. Welcome to XML
- All About Markup Languages
- All About XML
- Looking at XML in a Browser
- Working with XML Data Yourself
- Structuring Your Data
- Creating Well-Formed XML Documents
- Creating Valid XML Documents
- How XML Is Used in the Real World
- Online XML Resources
- Summary
- Q&A
- Workshop
- Day 2. Creating XML Documents
- Choosing an XML Editor
- Using XML Browsers
- Using XML Validators
- Creating XML Documents Piece by Piece
- Creating Prologs
- Creating an XML Declaration
- Creating XML Comments
- Creating Processing Instructions
- Creating Tags and Elements
- Creating CDATA Sections
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 3. Creating Well-Formed XML Documents
- What Makes an XML Document Well-Formed?
- Creating an Example XML Document
- Understanding the Well-Formedness Constraints
- Using XML Namespaces
- Understanding XML Infosets
- Understanding Canonical XML
- Summary
- Q&A
- Workshop
- Day 4. Creating Valid XML Documents: DTDs
- All About DTDs
- Validating a Document by Using a DTD
- Creating Element Content Models
- Commenting a DTD
- Supporting External DTDs
- Handling Namespaces in DTDs
- Summary
- Q&A
- Workshop
- Declaring Attributes in DTDs
- Day 5. Handling Attributes and Entities in DTDs
- Specifying Default Values
- Specifying Attribute Types
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 6. Creating Valid XML Documents: XML Schemas
- Using XML Schema Tools
- Creating XML Schemas
- Dissecting an XML Schema
- The Built-in XML Schema Elements
- Creating Elements and Types
- Specifying a Number of Elements
- Specifying Element Default Values
- Creating Attributes
- Summary
- Q&A
- Workshop
- Day 7. Creating Types in XML Schemas
- Restricting Simple Types by Using XML Schema Facets
- Creating XML Schema Choices
- Using Anonymous Type Definitions
- Declaring Empty Elements
- Declaring Mixed-Content Elements
- Grouping Elements Together
- Grouping Attributes Together
- Declaring all Groups
- Handling Namespaces in Schemas
- Annotating an XML Schema
- Summary
- Q&A
- Workshop
- Part I. In Review
- Well-Formed Documents
- Valid Documents
- Part II: At a Glance
- Day 8. Formatting XML by Using Cascading Style Sheets
- Our Sample XML Document
- Introducing CSS
- Connecting CSS Style Sheets and XML Documents
- Creating Style Sheet Selectors
- Using Inline Styles
- Creating Style Rule Specifications in Style Sheets
- Summary
- Q&A
- Workshop
- Day 9. Formatting XML by Using XSLT
- Introducing XSLT
- Transforming XML by Using XSLT
- Writing XSLT Style Sheets
- Using <xsl:apply-templates>
- Using <xsl:value-of> and <xsl:for-each>
- Matching Nodes by Using the match Attribute
- Working with the select Attribute and XPath
- Using <xsl:copy>
- Using <xsl:if>
- Using <xsl:choose>
- Specifying the Output Document Type
- Summary
- Q&A
- Workshop
- Day 10. Working with XSL Formatting Objects
- Introducing XSL-FO
- Using XSL-FO
- Using XSL Formatting Objects and Properties
- Building an XSL-FO Document
- Handling Inline Formatting
- Formatting Lists
- Formatting Tables
- Summary
- Q&A
- Workshop
- Part II. In Review
- Using CSS
- Using XSLT
- Using XSL-FO
- Part III: At a Glance
- Day 11. Extending HTML with XHTML
- Why XHTML?
- Writing XHTML Documents
- Validating XHTML Documents
- The Basic XHTML Elements
- Organizing Text
- Formatting Text
- Selecting Fonts: <font>
- Comments: <!-->
- Summary
- Q&A
- Workshop
- Day 12. Putting XHTML to Work
- Creating Hyperlinks: <a>
- Linking to Other Documents: <link>
- Handling Images: <img>
- Creating Frame Documents: <frameset>
- Creating Frames: <frame>
- Creating Embedded Style Sheets: <style>
- Formatting Tables: <table>
- Creating Table Rows: <tr>
- Formatting Table Headers: <th>
- Formatting Table Data: <td>
- Extending XHTML
- Summary
- Q&A
- Workshop
- Day 13. Creating Graphics and Multimedia: SVG and SMIL
- Introducing SVG
- Creating an SVG Document
- Creating Rectangles
- Adobe's SVG Viewer
- Using CSS Styles
- Creating Circles
- Creating Ellipses
- Creating Lines
- Creating Polylines
- Creating Polygons
- Creating Text
- Creating Gradients
- Creating Paths
- Creating Text Paths
- Creating Groups and Transformations
- Creating Animation
- Creating Links
- Creating Scripts
- Embedding SVG in HTML
- Introducing SMIL
- Summary
- Q&A
- Workshop
- Day 14. Handling XLinks, XPointers, and XForms
- Introducing XLinks
- Beyond Simple XLinks
- Introducing XPointers
- Introducing XBase
- Introducing XForms
- Summary
- Workshop
- Part III. In Review
- Part IV: At a Glance
- Day 15. Using JavaScript and XML
- Introducing the W3C DOM
- Introducing the DOM Objects
- Working with the XML DOM in JavaScript
- Searching for Elements by Name
- Reading Attribute Values
- Getting All XML Data from a Document
- Validating XML Documents by Using DTDs
- Summary
- Q&A
- Workshop
- Day 16. Using Java and .NET: DOM
- Using Java to Read XML Data
- Finding Elements by Name
- Creating an XML Browser by Using Java
- Navigating Through XML Documents
- Writing XML by Using Java
- Summary
- Q&A
- Workshop
- Day 17. Using Java and .NET: SAX
- An Overview of SAX
- Using SAX
- Using SAX to Find Elements by Name
- Creating an XML Browser by Using Java and SAX
- Navigating Through XML Documents by Using SAX
- Writing XML by Using Java and SAX
- Summary
- Q&A
- Workshop
- Day 18. Working with SOAP and RDF
- Introducing SOAP
- A SOAP Example in .NET
- A SOAP Example in Java
- Introducing RDF
- Summary
- Q&A
- Workshop
- Part IV. In Review
- Part V: At a Glance
- Day 19. Handling XML Data Binding
- Introducing DSOs
- Binding HTML Elements to HTML Data
- Binding HTML Elements to XML Data
- Binding HTML Tables to XML Data
- Accessing Individual Data Fields
- Binding HTML Elements to XML Data by Using the XML DSO
- Binding HTML Tables to XML Data by Using the XML DSO
- Searching XML Data by Using a DSO and JavaScript
- Handling Hierarchical XML Data
- Summary
- Q&A
- Workshop
- Day 20. Working with XML and Databases
- XML, Databases, and ASP
- Storing Databases as XML
- Using XPath with a Database
- Introducing XQuery
- Summary
- Q&A
- Workshop
- Day 21. Handling XML in .NET
- Creating and Editing an XML Document in .NET
- From XML to Databases and Back
- Reading and Writing XML in .NET Code
- Using XML Controls to Display Formatted XML
- Creating XML Web Services
- Summary
- Q&A
- Workshop
- Part V. In Review
- Appendix A. Quiz Answers
- Quiz Answers for Day 1
- Quiz Answers for Day 2
- Quiz Answers for Day 3
- Quiz Answers for Day 4
- Quiz Answers for Day 5
- Quiz Answers for Day 6
- Quiz Answers for Day 7
- Quiz Answers for Day 8
- Quiz Answers for Day 9
- Quiz Answers for Day 10
- Quiz Answers for Day 11
- Quiz Answers for Day 12
- Quiz Answers for Day 13
- Quiz Answers for Day 14
- Quiz Answers for Day 15
- Quiz Answers for Day 16
- Quiz Answers for Day 17
- Quiz Answers for Day 18
- Quiz Answers for Day 19
- Quiz Answers for Day 20
- Quiz Answers for Day 21
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Extending XHTML
The name Extensible Hypertext Markup Language might give you the impression that XHTML is designed to be extended. That's true. However, although you can technically extend XHTML, HTML browsers won't understand what you're doing. Let's take a look at an example.
In this example, you'll extend XHTML by adding to it a new element, <bold>, that will display its text in bold. Here's how you might declare this element in a DTD:
<!ELEMENT bold (#PCDATA)>
You also need the rest of the XHTML 1.0 Transitional DTD, so you start by creating a new parameter entity, which you can call XHTML1.0DTDEntity:
<!ELEMENT bold (#PCDATA)> <!ENTITY % XHTML1.0DTDEntity PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
Now to include the entire XHTML 1.0 Transitional DTD in the new DTD, you just use a reference to this parameter entity. Listing 12.11 shows how this works.
Example 12.11. Extending the XHTML 1.0 Transitional DTD (ch12_11.dtd)
<!ELEMENT bold (#PCDATA)> <!ATTLIST bold boldattribute CDATA #IMPLIED > <!ENTITY % XHTML1.0DTDEntity PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> %XHTML1.0DTDEntity;
Now you have a new DTD that supports not only the <bold> element, but also the rest of XHTML 1.0 Transitional. So you've extended XHTML. You can see this new DTD at work in Listing 12.12.
Example 12.12. Extending XHTML 1.0 Transitional as HTML (ch12_12.html)
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html SYSTEM "ch12_11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>
Extending XHTML
</title>
<link rel="stylesheet" href="ch12_13.css" />
</head>
<body>
<p>
This version of XHTML can make text <bold>bold</bold>.
</p>
</body>
</html>
To style the new <bold> element, you can use a CSS, such as the one in Listing 12.13.
Example 12.13. A Style Sheet for Extending XHTML 1.0 Transitional (ch12_13.css)
bold {font-weight: bold}
However, neither Internet Explorer nor Netscape Navigator will understand what to do with your extended XHTML. The reason for this is that you've given the XHTML document, ch12_12.html, the extension .html, which means that browsers will assume the fixed HTML element set and not even try to read in the DTD.
You can do a better job in this case if you treat ch12_12.html as XML instead of HTML. Listing 12.14 shows how that might work. In this version of the document, you're using an internal DTD (so as not to confuse Internet Explorer, which can't handle the DTD here as an external one) and the <?xml-stylesheet?> XML processing instruction to include a new version of the style sheet, ch12_15.css (to make sure the text in the <title> element will also be formatted for display), which is shown in Listing 12.15.
Example 12.14. Extending XHTML 1.0 Transitional as XML (ch12_14.xml)
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/css" href="ch12_15.css"?>
<!DOCTYPE html [
<!ELEMENT bold (#PCDATA)>
<!ENTITY % XHTML1.0DTDEntity PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
%XHTML1.0DTDEntity;
]>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>
Extending XHTML
</title>
</head>
<body>
<p>
This version of XHTML can make text <bold>bold</bold>.
</p>
</body>
</html>
Example 12.15. A Style Sheet Used to Extend XHTML 1.0 Transitional as XML (ch12_15.css)
bold {font-weight: bold}
title {display:block; font-size: 24pt}
Figure 12.7 shows the results of Listings 12.14 and 12.15. in Internet Explorer. Internet Explorer indeed downloads the XHTML 1.0 Transitional DTD, extends it with the new <bold> element, and produces the results shown in Figure 12.7.
)
Figure 12.7 Extending XHTML.
By treating the markup as XML, you are able to extend XHTML. That's not too bad because the XHTML DTDs still contain all the XHTML rules, such as which elements can contain which other elements and which attributes are required. The drawback is that you need to define from scratch all the formatting you want to use; you do this by defining your own style sheets or using someone else's.