Sunday, 8 January 2012

HTML DOM Nodes


In the DOM, everything in an HTML document is a node.

DOM Nodes

According to the DOM, everything in an HTML document is a node.
The DOM says:
  • The entire document is a document node
  • Every HTML element is an element node
  • The text in the HTML elements are text nodes
  • Every HTML attribute is an attribute node
  • Comments are comment nodes

DOM Example

Look at the following HTML document:
<html>
  <head>
    <title>DOM Tutorial</title>
  </head>
  <body>
    <h1>DOM Lesson one</h1>
    <p>Hello world!</p>
  </body>
</html>
The root node in the HTML above is <html>. All other nodes in the document are contained within <html>.
The <html> node has two child nodes; <head> and <body>.
The <head> node holds a <title> node. The <body> node holds a <h1> and <p> node.

Text is Always Stored in Text Nodes

A common error in DOM processing is to expect an element node to contain text.
However, the text of an element node is stored in a text node.
In this example: <title>DOM Tutorial</title>, the element node <title>, holds a text node with the value "DOM Tutorial".
"DOM Tutorial" is not the value of the <title> element!
However, in the HTML DOM the value of the text node can be accessed by the innerHTML property.
You can read more about the innerHTML property in a later chapter.

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