<body>
<div id="app">
<div>First Content</div>
<div>Second Content</div>
</div>
<script>
const app = document.getElementById('app');
console.log(app.innerText);
//output:
// => First Content
// => Second Content
console.log(app.innerHtml);
//output:
// => <div id="app">
// => <div>First Content</div>
// => <div>Second Content</div>
// => </div>
</script>
</body>