1. Accessing XML Documents Using DOM
Objectives
In this lesson, you will learn to:
Use XML DOM objects to perform the following tasks:
Validate an XML document against an XML
schema
Provide user-selected view of data stored in an
XML document
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2. Accessing XML Documents Using DOM
Problem Statement 8.D.1
The head office of CyberShoppe receives data in the form of
XML documents from its branches. In order to ensure
consistency of data sent by the branches, the head office
maintains the definitions for structures of documents in
schemas. On receiving data from branches, the head office
needs to verify that the data conforms to the schema for the
respective documents. For this, they need to write a script,
which validates the data stored in an XML document against
a schema.
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3. Accessing XML Documents Using DOM
Task List
Identify a mechanism to validate an XML document
against a schema.
Identify the objects required to access an XML
document through a scripting language.
Write the code to validate an XML document against
the schema.
Execute the code.
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4. Accessing XML Documents Using DOM
Task 1: Identify a mechanism to validate an XML
document against a schema.
In order to validate an XML document, you need to use a
validating parser. MSXML is a DOM-based validating
parser.
Result
You can use the XML DOM objects provided by MSXML in
order to ensure that the structure of the XML document
conforms to the schema.
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5. Accessing XML Documents Using DOM
Task 2: Identify the objects required to access an
XML document through a scripting language.
You can use the DOMDocument object to load an XML
document, parse it, and validate it.
You can use the properties of IXMLDOMParseError
object to display appropriate messages in case of an error.
You require another object called XMLSchemaCache to
load the schema document associated with the XML
document.
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6. Accessing XML Documents Using DOM
Task 2: Identify the … scripting language.
(Contd.)
The XMLSchemaCache Object
The XMLSchemaCache object is used to hold a
collection of schema documents that specify the rules to
which XML documents must conform.
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7. Accessing XML Documents Using DOM
Task 2: Identify the … scripting language.
(Contd.)
The following table describes some methods provided
by this object:
Method Description
add(namespaceURI, variable) This method adds a new schema to the collection and also associates
the specified namespaceURI with the schema.
addCollection(XMLSchemaColle This method adds schemas from other schema collections. It also
ction object) ensures that the namespaceURIs of the different schemas do not
clash.
get(namespaceURI) This method returns a node that contains the schema element.
namespaceURI(index number) This method returns the namespace that is associated with the
specified index number.
remove(namespaceURI) This method removes a schema from the collection.
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8. Accessing XML Documents Using DOM
Task 2: Identify the … scripting language. (Contd.)
Result
You can use the following XML DOM objects to validate
the XML document against a schema:
DOMDocument
IXMLDOMParseError
XMLSchemaCache
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9. Accessing XML Documents Using DOM
Task 3: Write the code to validate the XML
document against the schema.
To write a script that validates an XML document
against the schema, you need to follow the steps given
below:
Create the user interface to accept the name of the XML
document and the XML schema.
Write the code to load the XML document.
Write the code to add the XML schema in the
XMLSchemaCache object.
Write the code to validate the XML document against
the schema.
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10. Accessing XML Documents Using DOM
Task 4: Execute the code.
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11. Accessing XML Documents Using DOM
Just a Minute…
Write the code to add an XML schema called
“Products.xsd” to a schema collection.
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12. Accessing XML Documents Using DOM
Problem Statement 8.D.2
CyberShoppe sells its products through an e-commerce
Web site. Details about the products sold at CyberShoppe
need to be displayed. Product details include product name,
description, price, and quantity for all products. A customer
can choose to view the product details either as a table or
as a bulleted list.
©NIIT eXtensible Markup Language/Lesson 8/Slide 12 of 23

13. Accessing XML Documents Using DOM
Task List
Identify a mechanism to access an XML document
programmatically.
Identify the objects required to apply the style sheet to
the XML document during runtime.
Create the XML document.
Create the style sheets.
Write the code to apply a style sheet dynamically to
an XML document.
Execute the code.
©NIIT eXtensible Markup Language/Lesson 8/Slide 13 of 23

14. Accessing XML Documents Using DOM
Task 1: Identify a mechanism to access an XML
document programmatically.
Result
In this scenario, the customer can choose to view the
product details as a table or as a list. Therefore, you require
two style sheets. One of these style sheets needs to be
applied to the XML document during runtime. Therefore,
XML DOM can be used to access the XML document
containing product details. You can also use XML DOM to
dynamically apply an XSLT style sheet to an XML
document.
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15. Accessing XML Documents Using DOM
Task 2: Identify the objects required to apply the style
sheet to the XML document during runtime.
The XSLTemplate Object
The XSLTemplate object is the DOM object that is used to
access an XSLT style sheet.
This object is used to hold a cached style sheet that can
then be dynamically associated with an XML document.
Before a style sheet document can be applied to an XML
document, it is converted into a tree structure by the parser.
The XSLT tree structure is loaded into the memory of the
computer and used to process the XML document. This is
because the XSLTemplate object stores the complied XSLT
document. Therefore, you must first create an
XSLTemplate object.
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16. Accessing XML Documents Using DOM
Task 2: Identify the objects … runtime.(Contd.)
The XSLProcessor Object
To process an XML document by using a style sheet, you
must create an instance of the XSLProcessor object.
This object is used to apply a style sheet to an XML
document and then process that document.
The XSLProcessor object is supported only in IE 5.0 and
later.
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17. Accessing XML Documents Using DOM
Task 2: Identify the objects … runtime.(Contd.)
Result
In the given scenario, the product details contained in the
XML document need to be displayed either as a table or as a
list by using an XSLT style sheet. This can be done using
the XSLTemplate and XSLProcessor objects.
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18. Accessing XML Documents Using DOM
Task 3: Create the XML document.
Task 4: Create the style sheets.
Task 5: Write the code to apply a style sheet
dynamically to an XML document.
Task 6: Execute the code.
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19. Accessing XML Documents Using DOM
Just a Minute…
The following JavaScript code is used to create
XSLTemplate and DOMDocument objects. Identify the
errors in the code, if any.
custss= new
activexObject(MSXML.XSLTemplate.4)
custdomdoc=
activexobject( MSXML.ThreadedDOMdocument.4
.0);
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20. Accessing XML Documents Using DOM
Just a Minute…
Identify the errors in the following JavaScript code:
xslProcObject.output=xmlDocObject;
xslProcObject.Transform
alert(xslProcObject);
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21. Accessing XML Documents Using DOM
Problem Statement 8.P.1
CyberShoppe sells books through an e-commerce Web site.
A customer should be able to view book details, such as the
name of the book, the first and last names of the author, the
price, and the number of available books. A customer
should be given the choice of viewing the book details either
as a table or as a list. This choice is to be provided in a
drop-down list. Also ensure that the XML document is
loaded only once in the browser.
Hint: You can create a global xmldoc variable and load the
XML document in it. Use the OnLoad event of the BODY
element to load the XML document.
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22. Accessing XML Documents Using DOM
Summary
In this lesson, you learned that:
The XMLSchemaCache object is used to associate an
XML document with an XSD document.
The XMLSchemaCache object is used to hold a collection
of schema documents that specify the rules to which XML
documents must conform.
The XSLTemplate object is used to contain a compiled
XSL document.
The XSLProcessor object is used to apply style sheets on
a given XML document.
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23. Accessing XML Documents Using DOM
Summary (Contd.)
The XSLProcessor object is created using the
createProcessor() method.
The XSLProcessor object is associated with an XML
document by using the input property of the XSLProcessor
object.
The XSLProcessor object provides the transform() method
to transform an XML document according to the
information provided in an XSLT style sheet.
©NIIT eXtensible Markup Language/Lesson 8/Slide 23 of 23