Javascript Reference - HTML DOM getElementsByClassName() Method

The getElementsByClassName() method returns elements with the specified class name, as a NodeList object.

Browser Support


`getElementsByClassName`	Yes	9.0	Yes	Yes	Yes

Syntax

document.getElementsByClassName(classname)

Parameter Values

Parameter	Type	Description
classname	String	Required. The class name of the elements.

Return Value

A NodeList object, representing a collection of elements with the specified class name.

Example

The following code shows how to get all elements with the specified class name


<!DOCTYPE html>
<html>
<body>
<div class="example">First</div>
<div class="example">Second</div>
<button onclick="myFunction()">test</button>
<!--from   www.  jav  a2  s.  c o  m-->
<script>
function myFunction() {
    var x = document.getElementsByClassName("example");
    x[0].innerHTML = "Hello World!";
}
</script>

</body>
</html>

The code above is rendered as follows:

Example 2

The following code shows how to get all elements with both the "example" and "color" classes.


<!DOCTYPE html>
<html>
<body>
<div class="example">A</div>
<div class="example color">B</div>
<div class="example color">C</div>
<button onclick="myFunction()">test</button>
<!--  w w w.  j a  va 2  s .c o m-->
<script>
function myFunction() {
    var x = document.getElementsByClassName("example color");
    x[0].style.backgroundColor = "red";
}
</script>

</body>
</html>

The code above is rendered as follows:

Example 3

The following code shows how to get the count of elements with class="example".


<!DOCTYPE html>
<html>
<body>
<div class="example">A</div>
<div class="example">B</div>
<button onclick="myFunction()">test</button>
<p id="demo"></p>
<!--   ww w .j ava  2s  .  c  om-->
<script>
function myFunction() {
    var x = document.getElementsByClassName("example");
    document.getElementById("demo").innerHTML = x.length;
}
</script>

</body>
</html>

The code above is rendered as follows:

Example 4

The following code shows how to change the background color of all elements with class="example":


<!DOCTYPE html>
<html>
<head>
<style>
.example {<!--from  w  ww. j  a va2  s.c  o m-->
    border: 1px solid black;
    margin: 5px;
}
</style>
</head>
<body>
<div class="example">A</div>
<div class="example">B</div>
<p class="example">C</p>
<p>This is a <span class="example">span</span>.</p>
<button class="example" onclick="myFunction()">test</button>

<script>
function myFunction() {
    var x = document.getElementsByClassName("example");
    var i;
    for (i = 0; i < x.length; i++) {
        x[i].style.backgroundColor = "red";
    }
}
</script>

</body>
</html>

The code above is rendered as follows: