<!DOCTYPE html>
<html lang="en-US">
<body>
<p><span>span</span> inside paragraph</p>
<p>Click on the button to check whether paragraph contains span.</p>
<button onclick="myFunction()">Click Me</button>
<script>
var p = document.getElementsByTagName("p")[0];
var span = document.getElementsByTagName("span")[0];
function myFunction(){
alert(p.contains(span));
}
</script> </body>
</html>