<!DOCTYPE html>
<html>
<body>
<div class="example">
A div element with class="example"
</div>
<div class="example">
Another div element with class="example"
</div>
<p>A p element with class="example"</p>
<p>Click the button to find out how many elements with class "example" there are in this document.</p>
<button onclick="myFunction()">Try it</button>
<p><strong>Note:</strong> The getElementsByClassName() method is not supported in Internet Explorer 8 and earlier versions.</p>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementsByClassName("example");
document.getElementById("demo").innerHTML = x.length;
}
</script>
</body>
</html>