Firefox 19 has added an in-built native PDF reader. Here's the news for
Fx 19:
http://reviews.cnet.com/8301-13727_7-57570062-263/mozilla-puts-native-pdf-viewer-in-firefox-19/.Hoping
for Forms to control the opening application at user's end is asking for
a lot of security overrides, that are impossible in today's malicious
web world. For example, we wouldn't want programmers to have an option
to execute their applications, bypassing our anti-virus program 🙂