HTML DOM length Property
Attribute ObjectExample
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 |
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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