<!DOCTYPE html>
<html>
<body>
<h2 class="example">A heading with class="example"</h2>
<p class="example">A paragraph with class="example".</p>
<p>Click the button to add a background color all elements with class="example".</p>
<button onclick="myFunction()">Try it</button>
<button onclick="myFunction2()">Empty list</button>
<p><strong>Note:</strong> The querySelectorAll() method is not supported in Internet Explorer 8 and earlier versions.</p>
<script>
function myFunction() {
var x, i;
x = document.querySelectorAll(".example");
for (i = 0; i < x.length; i++) {
alert(i + ' ' + x[i].outerHTML);
}
}
function myFunction2() {
x = document.querySelectorAll(".example6");
alert(x.length);
}
</script>
</body>
</html>