I want to add some buttons after the print modal was showed. Just like the picture above. Anyone give some hands? Thank you.
>Solution :
Since printing is browser feature (think of client-side), you are not able to make changes/events normally in that area. Reason behind that is likely to be security (imagine a simple website printing lots of files from your printer when you are absent).
A likely solution would be opening blank page and using that page as "preview" page and add button there (you will still have to navigate user to this modal though).