Maybe there is already someone who make a blog about this, but the problem is that they are outdated as the codeforce website developed. Here I am to share it with you guys how to do that. It's just simple you just need to paste the script then press enter on the console by pressing F12, and it just automatically save the problem as pdf.

Here is the code: Click Here

[UPD 1]

Or instead just use vjudge crawler to convert it to pdf.