I'm using a custom bootstrap template and other users will be embedding youtube videos, which I want to be responsive to fit the theme.
What can I do to make the normal YouTube embed code, something like this:
<iframe width="560" height="315" src="https://www.youtube.com/embed/2jna3dWEnzo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
Into this formatting (simplified and with class added):
<iframe class="embed-responsive-item" src="https://www.youtube.com/embed/2jna3dWEnzo" allowfullscreen></iframe>
Any help would be fab!