Create full screen Iframe on button click

<style> .full{ position: fixed; background: #000; border:none; top: 0; right: 0; bottom: 0; left: 0; width: 100%; height: 100%; } </style> <iframe class="iframe" src="https://app.3schools.in"> </iframe> <button onclick="fullScreen()">Make Full Screen</button> <script> function fullScreen(){ document.querySelector('.iframe').classList.add('full'); } </script>