OPEN PDF within APPLICATION

I have designed Mobile Application with Html, CSS, and JQuery mobile as my university project but, I faced with one minor issue. By opening the DOCUMENT tab, the list of PDFs in DropBox appear on screen. By tapping on one of the PDFs, PDF file is opening on new TAB using google API and I am loosing header and footer to navigate back. I just want to open PDF within the Format. Pictures are provided for better understanding... My maximum budget for solving this issue is $50 as it is a university project and already finished.