HTML5 Canvas Print Function Update for Mobile

I have a certificate maker application that uses HTML5 Canvas. The user can create a certificate and then either print the certificate or save the certificate as a PNG. The application works correctly for desktop but for mobile browsers, the application prints the entire webpage and the png image download option renders an empty image. I am using the javascript code in the attached file. That is just the print function code, image download function and create canvas code for your reference on this project. I need it updated to work correctly on mobile browsers.