What's the difference between an element and a node in XML?

382
votes

I'm working in Java with XML and I'm wondering; what's the difference between an element and a node?

13
xmlxmlnode
Sure take a look at w3c. The datamodel is easy to understand - even for me! – xtofl
Great comment from forums.asp.net/t/443912.aspx/1#443940: The same as between fruit and apple. Every XmlElement is XmlNode, but not every XmlNode is XmlElement. XmlElement is just one kind of XmlNode. Others are XmlAttribute, XmlText etc. – atconway
An Element is part of the formal definition of a well-formed XML document, whereas a node is defined as part of the Document Object Model for processing XML documents. – Jool

13 Answers

272
votes

The Node object is the primary data type for the entire DOM.

A node can be an element node, an attribute node, a text node, or any other of the node types explained in the "Node types" chapter.

An XML element is everything from (including) the element's start tag to (including) the element's end tag.

69
votes

Different W3C specifications define different sets of "Node" types.

Thus, the DOM spec defines the following types of nodes:

  • Document -- Element (maximum of one), ProcessingInstruction, Comment, DocumentType
  • DocumentFragment -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
  • DocumentType -- no children
  • EntityReference -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
  • Element -- Element, Text, Comment, ProcessingInstruction, CDATASection, EntityReference
  • Attr -- Text, EntityReference
  • ProcessingInstruction -- no children
  • Comment -- no children
  • Text -- no children
  • CDATASection -- no children
  • Entity -- Element, ProcessingInstruction, Comment, Text, CDATASection, EntityReference
  • Notation -- no children

The XML Infoset (used by XPath) has a smaller set of nodes:

  • The Document Information Item
  • Element Information Items
  • Attribute Information Items
  • Processing Instruction Information Items
  • Unexpanded Entity Reference Information Items
  • Character Information Items
  • Comment Information Items
  • The Document Type Declaration Information Item
  • Unparsed Entity Information Items
  • Notation Information Items
  • Namespace Information Items

    • XPath has the following Node types:

    • root nodes
    • element nodes
    • text nodes
    • attribute nodes
    • namespace nodes
    • processing instruction nodes
    • comment nodes

    The answer to your question "What is the difference between an element and a node" is:

    An element is a type of node. Many other types of nodes exist and serve different purposes.

    36
    votes

    A Node is a part of the DOM tree, an Element is a particular type of Node

    e.g. <foo> This is Text </foo>

    You have a foo Element, (which is also a Node, as Element inherits from Node) and a Text Node 'This is Text', that is a child of the foo Element/Node

    27
    votes

    A node can be a number of different kinds of things: some text, a comment, an element, an entity, etc. An element is a particular kind of node.

    15
    votes

    As described in the various XML specifications, an element is that which consists of a start tag, and end tag, and the content in between, or alternately an empty element tag (which has no content or end tag). In other words, these are all elements:

    <foo> stuff </foo>
<foo bar="baz"></foo>
<foo baz="qux" />

    Though you hear "node" used with roughly the same meaning, it has no precise definition per XML specs. It's usually used to refer to nodes of things like DOMs, which may be closely related to XML or use XML for their representation.

    11
    votes

    An xml document is made of nested elements. An element begins at its opening tag and ends at its closing tag. You're probably seen <body> and </body> in html. Everything between the opening and closing tags is the element's content. If an element is defined by a self-closing tag (eg. <br/>) then its content is empty.

    Opening tags can also specify attributes, eg. <p class="rant">. In this example the attribute name is 'class' and its value 'rant'.

    The XML language has no such thing as a 'node'. Read the spec, the word doesn't occur.

    Some people use the word 'node' informally to mean element, which is confusing because some parsers also give the word a technical meaning (identifying 'text nodes' and 'element nodes'). The exact meaning depends on the parser, so the word is ill-defined unless you state what parser you are using. If you mean element, say 'element'.

    9
    votes

    A node is the base class for both elements and attributes (and basically all other XML representations too).

    8
    votes

    Element is the only kind of node that can have child nodes and attributes.

    Document also has child nodes, BUT
    no attributes, no text, exactly one child element.

    2
    votes

    A node is defined as:

    the smallest unit of a valid, complete structure in a document.

    or as:

    An object in the tree view that serves as a container to hold related objects.

    Now their are many different kinds of nodes as an elements node, an attribute node etc.

    1
    votes

    Now i know ,the element is one of node

    All node types in here"http://www.w3schools.com/dom/dom_nodetype.asp"

    Element is between the start tag and end in the end tag

    So text node is a node , but not a element.

    0
    votes

    An element is a type of node as are attributes, text etc.

    -3
    votes

    XML Element is a XML Node but with additional elements like attributes.

    <a>Lorem Ipsum</a>  //This is a node

<a id="sample">Lorem Ipsum</a>  //This is an element
    -7
    votes

    node & element are same. Every element is a node , but it's not that every node must be an element.