XML in a Nutshell, 3rd Edition

DOM Notation

The Document Object Model is intended to be operating system- and language- neutral; therefore, all DOM interfaces are specified using the Interface Description Language (IDL) notation defined by the Object Management Group. To conform to the language of the specification, this chapter and Chapter 25 will use IDL terminology when discussing interface specifics. For example, the word "attribute” in IDL-speak refers to what would be a member variable in C++. This should not be confused with the XML term “attribute,” which is a name-value pair that appears within an element’s start-tag.

The language-independent IDL interface must then be translated (according to the rules set down by the OMG) into a specific language binding. Take the following interface, for example:

interface NodeList {
  Node               item(in unsigned long index);
  readonly attribute unsigned long    length;
};

This interface would be expressed as a Java interface like this:

package org.w3c.dom;
  
public interface NodeList {
    public Node item(int index);
  
    public int getLength( );
  
}

The same interface would be described for ECMAScript this way:

Object NodeList The NodeList object has the following properties: length This read-only property is of type Number. The NodeList object has the following methods: item(index) This method returns a Node object. The index parameter is of type Number. Note: This object can also be dereferenced using square bracket notation (e.g. obj[1]). Dereferencing with an integer index is equivalent ...