innerHTML is a property that allows you to get and modify the HTML content inside an element. It gives full control over the content, including inserting new tags.

element.innerHTML = 'new HTML-tag';

Example of replacing an element’s content

document.getElementById('box').innerHTML = '<strong>New Text</strong>';

You can also add new HTML markup by replacing the entire content

let list = document.getElementById('list');
list.innerHTML = '<li>Element 1</li><li>Element 2</li>';

innerHTML lets you manipulate the contents of an element, but it requires caution. If you’re working with dynamic data, you must be careful to avoid injecting unwanted HTML into the code.