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And we've been busy here logging the fixing of old bugs and the discovery of new ones due to the release of FMP 14.
You can't perform scripts or button options by clicking something in a PDF. You may not even have FileMaker open at that time.
But there is some capability to do what you describe, but it's rather ugly.
You could set up a field on your layout to output text like this:
and (whether or not it is formatted with underlines), it becomes a clickable link in the PDF. IT's ugly as you can't hide the http text behind an easier to read label like you can here in this forum or on a typical web page, but it has worked for me in the past.