How to render HTML/CSS/JS on the server?

Question

HTML

Good day.
There is a goal - to check on the server side the results of two html + css + js codes for the similarity of the final result (visually).
What are the best goals for this?
There was an idea to write a handler with chromium in java, upload images using canvas, and then compare - but this is hemorrhoids.
Maybe there are ready-made solutions, or at least libraries for rendering pages?

Answer 1

phantomjs (or its derivatives) can take screenshots.
or selenium, can also take screenshots.