XML DOM Notes

Introduction:

XML DOM is the Programming Interface for XML Documents.

It Defines the Way an XML Document can be Accessed and Manipulated.

It is designed to be used with any Programming Language and any Operating System.

An XML Parser can be used to Load an XML Document into Memory.

The DOM is represented in a Tree View of the XML Document.

A Node Interface Model is used to access elements in the Node Tree.

Most Commonly Used Node Types

Node Type	Example
Document Type	<!DOCTYPE food SYSTEM "food.dtd">
Processing Instructions	<?xml version = "1.0"?>
Element	<drink type = "beer">CarlsBerg</drink>
Attribute	type = "beer"
Text	CarlsBerg

Parsing

A Parser is Required - to Read, Update, Create and Manipulate XML Documents
- The Microsoft XML Parser
  
  The Microsoft XML Parser is a COM component that comes with Internet Explorer.
  The Parser is available to Scripts inside HTML and ASP files.
  It supports JavaScript, VBScript, Perl, VB, Java, C++, W3C XML 1.0, XML DOM,
  DTD and Validation
  - To Create an XML Document Object
    1. JavaScript
      
      var ObjectName = new ActiveXObject("Microsoft.XMLDOM")
    2. VBScript
      
      Set ObjectName = CreateObject("Microsoft.XMLDOM")
    3. ASP
      
      set ObjectName = Server.CreateObject("Microsoft.XMLDOM")
- Loading an XML File Into the Parser
```
            <SCRIPT Type = "Text/JavaScript">
              ObjectName = new ActiveXObject("Microsoft.XMLDOM")
              ObjectName.async = "false"
              ObjectName.load("filename.xml")
                   // Processing Goes Here //
              </SCRIPT>
          
```
- Loading Pure XML Text into the Parser
```
            <SCRIPT Type = "Text/JavaScript">
              var text = "<note>"
              text = text + "<to>Bob</to><from>Bill</from>"
              text = text + "<heading>Reminder</heading>"
              text = text + "<body>Don't forget me this weekend</body>"
              text = text + "</noteto>"
            </SCRIPT>
          
```
  **Note**
  The LoadXML method, not the Load method, is Used to Load a Text String!

ParseError

The ParseError Object is used to retrieve Error Information from the Parser.

Property	Description
[ObjectName].ParseError.ErrorCode	Numeric Error Code
[ObjectName].ParseError.Reason	String Error Reason
[ObjectName].ParseError.Line	LInt Error Line Number
[ObjectName].ParseError.LinePos	LInt Error Line Position
[ObjectName].ParseError.SrcText	String Error Line of Code
[ObjectName].ParseError.URL	URL Pointing to the Document
[ObjectName].ParseError.FilePos	LInt Error File Position

Validators

Programs Used to Validate the Opens and Closes of the <TAGS> in the XML File

Accessing The DOM

Access the Node Tree Elements by Number or by Name

Traversing the Node Tree By Number

Example:VBScript

            XMLDoc = CreateObject("Microsoft.XMLDOM")
            XMLDoc.async = "false"
            XMLDoc.load("FileName.xml")
            For Each X in XMLDoc.documentElement.childNodes
              Document.Write(X.nodename & ' ' & X.text)
            Next X

Traversing the Node Tree By Name

Example:JavaScript

            XMLDoc = new ActiveXObject("Microsoft.XMLDOM")
            XMLDoc.async = "false"
            XMLDoc.load("FileName.xml")
            HTMLObjectName.innerText = XMLDoc.getElementsByTagName("tag").item(n).text

The HTTPRequest Object

Provides Client-Side Communcation with a Server

Example:VBScript

        XMLDoc = CreateObject("Microsoft.XMLHTTP")

Example:JavaScript

        XMLHTTP = new ActiveXObject("Microsoft.XMLHTTP")

Get XML -

Opens and Reads from a file on the Server

Example:Internet Explorer

            XMLHTTP = new ActiveXObject("Microsoft.XMLHTTP")
            XMLHTTP.open("GET", "FileName", false)
            XMLHTTP.send()
            XMLDoc = XMLHTTP.responseText

Example: Netscape

            XMLHTTP = new XMLHttpRequest();
            XMLHTTP.open("GET", "FileName", false);
            XMLHTTP.send(null);
            XMLDoc = XMLHTTP.responseText;

Send XML -

Opens and Writes to a File on the Server

Example: ASP

            XMLHTTP = new ActiveXObject("Microsoft.XMLHTTP")
            XMLHTTP.open("POST", "FileName.asp", false)
            XMLHTTP.send(XMLDoc)
            XMLDocResponse = XMLHTTP.responseText

Example: VBScript

            XMLDOC = Server.CreateObject("Microsoft.XMLDOM")
            XMLDOC.async = false
            XMLDOC.load(request)
            For Each X in XMLDOC.documentElement.childNodes
              if X.NodeName = "TagName" then name = X.Text
            Next
            Response.Write(name)

HTTPRequest Properties

Property	Description
readyState	Returns the State of the Document
responseBody	Returns the response as an array of Unsigned Bytes
responseStream	Returns the response as an IStream
responseText	Returns the response as a String
responseXML	Returns the response as an XML Document
status	Returns the Status Code as a Number
statusText	Returns the Status as a String

HTTPRequest Methods

Method	Description
abort()	Cancels the Current HTTP Request
getAllResponseHeaders()	Returns the Value of the HTTP Headers
getResponseHeader(headerName)	Returns the Value of a specified HTTP Header
Open(method,url,async,uerid,password)	Opens an HTTP Request
send()	Sends the HTTP Request to the Server
setRequestHeader(headerName,headerValue)	Specifies the Name of an HTTP Header

XML DOM NodeTypes

Node Types

nodeType	nodeTypeString	nodeName	nodeValue
1	element	tagName	null
2	attribute	name	value
3	text	#text	content of node
4	cdatasection	#cdata-section	content of node
5	entityreference	entity reference name	null
6	entity	entity name	null
7	processinginstruction	target	content of node
8	comment	#comment	comment text
9	document	#document	null
10	documenttype	doctype name	null
11	documentfragment	#document fragment	null
12	notation	notation name	null

Node Types Named constants

NodeType	Named Constant
1	ELEMENT_NODE
2	ATTRIBUTE_NODE
3	TEXT_NODE
4	CDATA_SECTION_NODE
5	ENTITY_REFERENCE_NODE
6	ENTITY_NODE
7	PROCESSING_INSTRUCTION_NODE
8	COMMENT_NODE
9	DOCUMENT_NODE
10	DOCUMENT_TYPE_NODE
11	DOCUMENT_FRAGMENT_NODE
12	NOTATION_NODE

XML DOM Node Object

Properties

Property	Description
attributes	Returns a NamedNodeMap containing all node attributes
childNodes	Returns a NodeList containing all child nodes
firstChild	Returns the nodes' first child node
lastChild	Returns the nodes' last child node
nextSibling	Returns the nodes' next sibling node
nodeName	Returns the Node Name, depending on the type
nodeType	Returns the node type as a number
ownerDocument	Returns the nodes' root node
parentNode	Returns the nodes' parent node
previousSibling	Returns the nodes' previous sibling node
basename	Returns the nodeName without the namespaces
dataType	Sets/Returns the nodes' data type
definition
nodeTypeString	Returns the node type as a string
nodeTypedValue
specified	Returns if the nodeValue is specified in the DTD/Schema
text	Sets/Returns nodes' text and all of it's child nodes
xml	Sets/Returns nodes' xml and for all it's child nodes

Methods

Method	Description
appendChild(newChild)	Appends node newChild after last childNode
cloneNode(boolean)	Returns exact clone if boolean = true, all childNodes are cloned too
inserBefore(newNode,refNode)	Inserts newNode before refNode
removeChild(nodeName)	Removes childNode nodeName
replaceChild(newNode,oldNode)	Replaces childNode oldNode with newNode
selectNodes(pattern)
selectSingleNode(pattern)
transformNode(stylesheet)	Processes the node and childNodes with XSL stylesheet and returns the result

The XML DOM NodeList Object

Represents a node and childNodes as a node tree

Properties

Property	Description
length	Number of Nodes
nextNode()	Returns the next object in the node list
reset()	Resets the pointer to the first node

Methods

Method Description
item Returns specific node in the nodelist

Method	Description
item	Returns specific node in the nodelist

The XML DOM Document Object

The Root Element in the Node Tree

Properties

Property	Description
documentElement	Root Element of the Document
doctype	Returns the DTD or Schema for the document
implementation	Returns the implementation object for this document

Methods

Method	Description
createAttribute(attributeName)	Creates an attribute node with the specified name
createCDATASection(text)	Creates CDATA section with specified text
createComment(text)	Creates comment section with the specified text
createDocumentFragment()	Creates an empty documentFragment object
createElement(tagName)	Creates an Element with the Specified Tag Name
createEntityReference(referenceName)	Creates an entityReference with the specified name
createProcessingInstruction(target,text)	Creates a processingInstruction node with the specified target and text
createTextNode(text)	Creates a text node, containing the text
getElementByTagName(tagName)	Returns specified node and it's c hildNodes as a nodelist

The XML DOM Element Object

Represents the Element Nodes in the Document

Properties

Property Description
tagName Sets/Returns the Name of the Node

Property	Description
tagName	Sets/Returns the Name of the Node

Methods

Method	Description
getAttribute(attributeName)	Returns the Value of the Specified Attribute
getAttributeNode(attributeName)	Returns the specified attribute node as an Object
getElementsByTagName(tagName)	Returns the specified Node and it's childNodes as a Nodelist
normalize()	Puts the text nodes for this element and it's child nodes into one text node
removeAttribute(attributeName)	Removes the specified attributes value Restores Default value if it exists
removeAttributeNode(attributeNode)	Removes the specified attribute node
setAttribute(attributeName,attributeValue)	Inserts a new Attribute
setAttributeNode(attributeNodeName)	Inserts new Attribute Node

The XML DOM Attr Object

Returns an Attribute of an Element Object as an Attribute Node

Properties

Property	Description
name	Sets/Returns the Attributes Nname
specified	Returns boolean indicating if the node's value is set in the document
value	Sets/Returns the Attributes value

The XML DOM Text Object

Represents the Text Inside an Element as a Node

Methods

Method	Description
splitText(n)	Splits the text of the specified character and returns the rest of the text

CDATA

Represented by the CDATASection in a document
Used to escape parts of text which would be interpreted as MarkUp
The XML DOM Comment Object

Representes the Comment Nodes in a Document
No Node Name, but the nodeValue is the Comment Text

Hosted by www.Geocities.ws