Is it possible to catpure a PDF (at least 1 page) that is in an iframe or embed tag ?

[sscotti]

I have a situation where I'm interested in capturing a PDF document that is on an HTML page either in an iframe or as the src for an embed tag. In both instances, the src is a data-url, and the reason I am interested is because I'm filling fillable PDF forms using pdf-lib library and if I need to edit the form fields after they are filled it is apparently not possible to "flatten" the form using that library. It works really well for instances where the forms fields are all filled and the form is just flattened.

I am thinking that if in those few instances where editing needs to be done that I can do a "screen grab" (they are usually just one page and can be displayed fully in a browser window.

I've tried a few things, but it looks like html2canvas cannot capture iframe contents or embed tag (and probably object) contents ?

One of the errors I am seeing is:

Uncaught (in promise) Error: Element is not attached to a Document
Ts html2canvas.min.js:20
e html2canvas.min.js:20

etc.