Hi,
Do you mean a web page that is loaded via the normal Safari browser or you are building an iOS app.
If an iOS app.
Then since you are already using iOS code, you may as well do the screen capture via the iOS code.
Imagine you have a Hype HTML/scene load in a WKWebView in the iOS app.
The hype shows a button.
When that button is clicked. It sends a message to the iOS app to capture the screen.
But
1, If writing the canvas is beyond you then doing the code in Hype and iOS may also.
It just took me about an Hour to figure out the iOS coding to do the capture ( me being rusty )
2, The image will show the button and what ever else was showing at the time. Is this really what you want ?
Please add some detail.
Thanks