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- 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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Validating XML Documents by Using DTDs
On Day 6, "Creating Valid XML Documents: XML Schemas," you saw how to use JavaScript to validate XML documents with XML schemas. Today, you'll see how to validate XML documents with DTDs by using JavaScript. By default, Internet Explorer validates documents by using DTDs. (You can turn validation off if you set the validateOnParse property of a document to false; it's set to true by default). However, you won't know how the validation went unless you check the parseError object.
Let's take a look at an example. In this case, you start by giving today's sample XML document, ch15_01.xml, a DTD, as shown in Listing 15.7.
Example 15.7. Adding a DTD to the XML Sample (ch15_07.xml)
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE session [
<!ELEMENT session (committee)*>
<!ELEMENT committee (title, number, subject, date, attendees)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT number (#PCDATA)>
<!ELEMENT subject (#PCDATA)>
<!ELEMENT date (#PCDATA)>
<!ELEMENT attendees (senator)*>
<!ELEMENT senator (firstName, lastName)>
<!ELEMENT firstName (#PCDATA)>
<!ELEMENT lastName (#PCDATA)>
<!ATTLIST committee
type CDATA #REQUIRED>
<!ATTLIST senator
status CDATA #REQUIRED>
]>
<session>
<committee type="monetary">
<title>Finance</title>
<number>17</number>
<subject>Donut Costs</subject>
<date>7/15/2005</date>
<attendees>
<senator status="present">
<firstName>Thomas</firstName>
<lastName>Smith</lastName>
</senator>
<senator status="absent">
<firstName>Frank</firstName>
<lastName>McCoy</lastName>
</senator>
<senator status="present">
<firstName>Jay</firstName>
<lastName>Jones</lastName>
</senator>
</attendees>
</committee>
</session>
Now you need to write the code that checks the parseError object to see whether there were any validation errors. You can do that by using the parseError object's errorCode, url, line, linepos, errorString, and reason properties and displaying the error if there was an error.
First, to be informed of the document's status as validation occurs, you can assign the name of a new method, changeHandler, to the document's onreadystatechange event:
xmlDocumentObject.onreadystatechange = changeHandler
Now you need to write the changeHandler method. When the document is loaded, you check the parseError object's errorCode property. If it is nonzero, you know there has been an error, and you can display it this way in the changeHandler method:
function changeHandler()
{
if(xmlDocumentObject.readyState == 4){
var errorText = xmlDocumentObject.parseError.srcText
errorText = xmlDocumentObject.parseError.srcText.replace(/\</g, "<" )
errorText = errorText.replace(/\>/g, ">")
if (xmlDocumentObject.parseError.errorCode != 0) {
displayDIV.innerHTML = "Error in " +
xmlDocumentObject.parseError.url +
" line " + xmlDocumentObject.parseError.line +
" position " + xmlDocumentObject.parseError.linepos +
":<BR>Source: " + errorText +
"<BR>" + xmlDocumentObject.parseError.reason +
"<BR>" + "Error: " +
xmlDocumentObject.parseError.errorCode
}
else {
displayDIV.innerHTML = "Document validated OK.<BR>"
}
}
}
Listing 15.8 shows the full code.
Example 15.8. Validating an XML Document by Using a DTD (ch15_08.html)
<HTML>
<HEAD>
<TITLE>
Validation With DTDs
</TITLE>
<SCRIPT LANGUAGE="JavaScript">
var xmlDocumentObject
function validateDocument()
{
xmlDocumentObject = new ActiveXObject("microsoft.XMLDOM")
xmlDocumentObject.onreadystatechange = changeHandler
xmlDocumentObject.load('ch15_07.xml')
}
function changeHandler()
{
if(xmlDocumentObject.readyState == 4){
var errorText = xmlDocumentObject.parseError.srcText
errorText =
xmlDocumentObject.parseError.srcText.replace(/\</g, "<")
errorText = errorText.replace(/\>/g, ">")
if (xmlDocumentObject.parseError.errorCode != 0) {
displayDIV.innerHTML = "Error in " +
xmlDocumentObject.parseError.url +
" line " + xmlDocumentObject.parseError.line +
" position " + xmlDocumentObject.parseError.linepos +
":<BR>Source: " + errorText +
"<BR>" + xmlDocumentObject.parseError.reason +
"<BR>" + "Error: " +
xmlDocumentObject.parseError.errorCode
}
else {
displayDIV.innerHTML = "Document validated OK.<BR>"
}
}
}
</SCRIPT>
</HEAD>
<BODY>
<H1>
Validation With DTDs
</H1>
<INPUT TYPE="BUTTON" VALUE="Validate document"
ONCLICK="validateDocument()">
<BR>
<BR>
<DIV ID="displayDIV"></DIV>
</BODY>
</HTML>
The document with the DTD, ch15_07.xml, validates, as shown in Figure 15.5.
)
Figure 15.5 Validating an XML document by using a DTD.
What if there were an error in the DTD? Say that we had omitted the <attendees> element from the declaration of the <committee> element, like this:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE session [
<!ELEMENT session (committee)*>
<!ELEMENT committee (title, number, subject, date)>
.
.
.
Figure 15.6 shows how this error is reported when the document is validated.
)
Figure 15.6 Catching a validation error by using a DTD.