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HTML DOM length Propery

< Attribute Object

Example

Get the number of attributes of a <button> element:

var x = document.getElementsByTagName("BUTTON")[0].attributes.length;

The result of x could be:

2
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More "Try it Yourself" examples below.


Definition and Usage

The length property returns the number of nodes in a NamedNodeMap object.

A Node object's attributes is an example of a NamedNodeMap object.

This property is read-only.

Tip: Use the item() method to return a node at the specified index in a NamedNodeMap object.


Browser Support

Property
length Yes Yes Yes Yes Yes

Note: In Internet Explorer 8 and earlier, the length property for attributes will return the number of all possible attributes for an element.


Syntax

namednodemap.length

Technical Details

Return Value: A Number, representing the number of attribute nodes in the nodemap
DOM Version Core Level 1

Examples

More Examples

Example

Loop through all attributes of a <button> element and output the name of each attribute:

var txt = "";
var x = document.getElementById("myBtn").attributes;

var i;
for (i = 0; i < x.length; i++) {
    txt += "Attribute name: " + x[i].name + "<br>";
}

The result of txt will be:

Attribute name: id
Attribute name: onclick
Attribute name: class
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Example

Find out how many attributes an <img> element have:

var x = document.getElementById("myImg").attributes.length;

The result of x will be:

5
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Example

Loop through all attributes of an <img> element and output each attribute's name and value:

var txt = "";
var x = document.getElementById("myImg");

var i;
for (i = 0; i < x.attributes.length; i++) {
    txt = txt + x.attributes[i].name + " = " + x.attributes[i].value + "<br>";
}
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< Attribute Object