XML Demystified

CHAPTER 10 MSXML
details of any errors that might have occurred. This is an instance of the
IXMLDOMParseError object. It checks if the errorCode is not zero, which means
an error occurred. If so, then the error message is displayed on the screen.
The sixth line displays the XML document in the text area of the HTML page.
Look carefully and you’ll notice that the line references the XML property of the
objXML variable. Remember that the objXML variable references the DOMDocument.
The XML property of the DOMDocument contains the XML representation of the
DOMDocument. Remember, the DOM is a tree type structure. The XML property
essentially serializes the DOM back to its familiar markup form.
Adding a New Element
The XML document contains information about CDs. Each CD has a upc attribute
and five child elements. Add the following CD to the catalog:
Phish
Live Phish, Vol. 15
26.99
ELEKTRA/WEA
2002-10-29
You’ll need to use four different functions to determine where to place the new
CD within the XML document. These functions are
• InsertFirst() Put the new entry at the beginning of the list
• InsertLast() Put the new entry at the end of the list
• InsertBefore() Put the new entry before the CD with the given upc
attribute
• InsertAfter() Put the new entry after the CD with the given upc attribute
Each function is called by an option on the HTML form. Options appear in the
first column of the table. The user of the application decides the position of the new
CD within the XML document by selecting the appropriate option.
The first two options place the new CD at the beginning or at the end of the XML
document, respectively. The last two options require the user to specify a UPC. The
UPC is the identifier for a CD that’s already in the XML document. The function
then places the new CD either before or after the CD that the user specifies.
The second column contains a text area containing information about the new
CD. We’ve provided a default value when the page loads, but you can change this
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