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loadXML

completely loaded and ready for use. This value is easy to mimic by assigning an

onload

event handler.

It’s also easy to simulate

readyState 1

, which indicates that the XML DOM has just started loading.

The other ready states aren’t as important and even more difficult — if not impossible — to simulate.

The two methods that affect the

readyState

property are

loadXML()

and

load()

. The

loadXML()

method is easy to update because it’s your creation. Just add two lines of code:

Document.prototype.loadXML = function (sXml) {

this.__changeReadyState__(1);

var oParser = new DOMParser();

var oXmlDom = oParser.parseFromString(sXml, “text/xml”);

while (this.firstChild) {

this.removeChild(this.firstChild);

}

for (var i=0; i < oXmlDom.childNodes.length; i++) {

var oNewNode = this.importNode(oXmlDom.childNodes[i], true);

this.appendChild(oNewNode);

}

this.__changeReadyState__(4);

};

The updated

loadXML()

method sets the

readyState

at the beginning and

at the end.

To update the

load()

method, start by creating a pointer to the original load method:

Document.prototype.__load__ = Document.prototype.load;

Next, define a new

load()

method that sets the

readyState

property to

and then calls the original

load()

method:

Document.prototype.load = function (sURL) {

this.__changeReadyState__(1);

this.__load__(sURL);

};

In order to set the

readyState

property to

at the right time, use the

onload

event handler. Because

you can only assign an event handler after the XML DOM object has been instantiated, this must take

place back in the

XmlDom

constructor:

function XmlDom() {

if (window.ActiveXObject) {

var arrSignatures = [“MSXML2.DOMDocument.5.0”, “MSXML2.DOMDocument.4.0”,

“MSXML2.DOMDocument.3.0”, “MSXML2.DOMDocument”,

“Microsoft.XmlDom”];

for (var i=0; i < arrSignatures.length; i++) {

try {

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Chapter 15

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