MORE ON THE FILEMAKER V13.0v2 FMP URL scheme:
FileMaker released version 13.0v2 on April 3, 2014. Its primary new feature was an improvement to their “FMP” URL Scheme. To understand what this is and why this is such a big deal, first a discussion on FMP URLs.
The most important aspect of being able to fully integrate live web controls into FileMaker layouts is the use of FileMaker’s “fmp://” protocol.
Objects within a Web Viewer can use this protocol to send messages directly to your FileMaker databases, locally and without the need for a web server to host the files and without the need for the Web Publishing Engine to supply the data.
Much more at the link on why it is important and lots of concrete examples!