From MozillaZine Knowledge Base

Revision as of 03:28, 10 March 2005

Until Mozilla fully supports the W3C's Document Object Model Load and Save, the easiest way to serialize and deserialize DOM trees is to use the following interfaces:

• nsIDOMSerializer to serialize DOM trees to strings or to files
• nsIDOMParser to deserialize XML from strings into DOM trees
• nsIXMLHttpRequest to deserialize XML from files into DOM trees

Although nsIDOMParser does have a method named parseFromStream(), it's actually easier to use nsIXMLHttpRequest (yes, it works for local and remote files).

Serializing DOM trees to Strings

First, create a DOM tree using code like this.

Now, let's serialize doc -- the DOM tree -- to a string:

var serializer = new XMLSerializer();
var xml = serializer.serializeToString(doc);

Serializing DOM trees to files

First, create a DOM tree using code like this.

Now, let's serialize doc -- the DOM tree -- to a file:

var serializer = new XMLSerializer();
var foStream = Components.classes["@mozilla.org/network/file-output-stream;1"].createInstance(Components.interfaces.nsIFileOutputStream);
var file = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile);
file.initWithPath("ProfD");   // %Profile% directory
file.append("extensions");   // extensions directory
file.append("{5872365E-67D1-4AFD-9480-FD293BEBD20D}");   // GUID of your extension
file.append("myXMLFile.xml");   // filename
foStream.init(file, 0x02 | 0x08 | 0x20, 0664, 0);   // write, create, truncate
serializer.serializeToFile(doc, foStream, "IS0-8859-1");   // rememeber, doc is the DOM tree
foStream.close();

Deserializing Strings into DOM Trees

var theString="<people><person first-name="eric" middle-initial="h" last-name="jung"><address street="321 south st" city="denver" state="co" country="usa"/><address street="123 main st" city="arlington" state="ma" country="usa"/></person><person first-name="jed" last-name="brown"><address street="321 north st" city="atlanta" state="ga" country="usa"/><address street="123 west st" city="seattle" state="wa" country="usa"/><address street="321 south avenue" city="denver" state="co" country="usa"/></person></people>";
var parser = new DOMParser();
var dom = parser.parseFromString(theString, "text/xml");

Deserializing Files into DOM Trees

Coming soon