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Checking the node type

You can check the type of node by using the

nodeType

property:

alert(document.nodeType); //outputs “9”

alert(document.documentElement.nodeType); //outputs “1”

In this example,

document.nodeType

returns

, which is equal to

Node.DOCUMENT_NODE

, and

docu-

ment.documentElement.nodeType

returns

, which is equal to

Node.ELEMENT_NODE

You can also match up these values with the

Node

constants:

alert(document.nodeType == Node.DOCUMENT_NODE); //outputs “true”

alert(document.documentElement.nodeType == Node.ELEMENT_NODE); //outputs “true”

This code works in Mozilla 1.0+, Opera 7.0+, and Safari 1.0+. Unfortunately, Internet Explorer doesn’t

support these constant values, so this code causes an error. You can remedy the situation by defining

your own constants that match the node type constants, such as the following:

if (typeof Node == “undefined”) {

var Node = {

ELEMENT_NODE: 1,

ATTRIBUTE_NODE: 2,

TEXT_NODE: 3,

CDATA_SECTION_NODE: 4,

ENTITY_REFERENCE_NODE: 5,

ENTITY_NODE: 6,

PROCESSING_INSTRUCTION_NODE: 7,

COMMENT_NODE: 8,

DOCUMENT_NODE: 9,

DOCUMENT_TYPE_NODE: 10,

DOCUMENT_FRAGMENT_NODE: 11,

NOTATION_NODE: 12

}

The other option is to use the integer literals (although this may get confusing because not many people

have memorized the node type values).

Dealing with attributes

As mentioned previously, only

Element

nodes have attributes even though the

Node

interface has an

attributes

method that is inherited by all node types. The attributes property for an

Element

node is

NamedNodeMap

, which provides several methods for accessing and manipulating its contents:

getNamedItem(

name

)

— returns the node whose

nodeName

property is equal to

name

removeNamedItem(

name

)

— removes the node whose

nodeName

property is equal to

name

from the list

setNamedItem(

node

)

— adds the

node

into the list, indexing it by its

nodeName

property

item(

pos

)

— just like

NodeList

, returns the node in the numerical position

pos

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DOM Basics

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