how to save the document that's open in Internet Explorer using VBA

I would like to come up with a way to save the document that's open in Internet Explorer from my Access 2010 program using VBA.

Users enter a code number on the same web site over and over. Each code number entered displays a PDF document in a new tab in Internet Explorer. I'd like to save the PDF document that's open in either the most recently opened tab or the tab that has the focus.

Any ideas on how I could do this?