How to add a button to the bottom of a Webview scroll space

Question

Looking for a way to add a button to the bottom of a WKWebView's scroll region. The effect I want is to be able to scroll to the bottom of the content and have a UIButton be at the bottom, think of it as a call to action to go to the next view.

One solution would be to create a UIScrollView, expand the webView to the height of the content and add it to the scrollview, then add a button to the bottom. Thinking there might be a easier way to do the same.

Note that I can't add to the HTML in the control.