Javascript Reference - HTML DOM getElementsByClassName() Method

The getElementsByClassName() method returns a collection of an element's child elements with the specified class name, as a NodeList object.

Browser Support


`getElementsByClassName`	Yes	9.0	Yes	Yes	Yes

Syntax

element.getElementsByClassName(classname)

Parameter Values

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

Return Value

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

Example

The following code shows how to change the text of the first list item.


<!DOCTYPE html>
<html>
<body>
<ul class="example">
  <li class="child">A</li>
  <li class="child">B</li>
</ul><!--  w  ww . ja  va 2 s .co m-->
<button onclick="myFunction()">test</button>
<script>
function myFunction() {
    var list = document.getElementsByClassName("example")[0];
    list.getElementsByClassName("child")[0].innerHTML = "Milk";
}
</script>

</body>
</html>

The code above is rendered as follows:

Example 2

The following code shows how to change the background color of the second element inside of a <div> element.


<!DOCTYPE html>
<html>
<head>
<style>
div {<!-- w w  w  . j  a va2 s  . c  om-->
    border: 1px solid black;
    margin: 5px;
}
</style>
</head>
<body>

<div id="myDIV">
  <p class="child">First p element</p>
  <p class="child">Second p element</p>
  <p class="child">Third p element</p>
</div>
<button onclick="myFunction()">test</button>
<script>
function myFunction() {
    var x = document.getElementById("myDIV");
    x.getElementsByClassName("child")[1].style.backgroundColor = "red";
}
</script>

</body>
</html>

The code above is rendered as follows: