Automation of Chrome / Firefox Plugin installation

I have web based software product for which developer has created plugin, which needs to be installed respectively either in chrome / firefox before users starts using the access through any of these 2 browsers. This software is restricted to run only on these 2 browsers owing to plugin installation need. Users are spread across globe and educating them to how to install the plugin is been a hard task. Hence I am looking for some kind of automation, on click of a button, user should be able to install the plugin automatically on any of these browsers from the respective available plugin files. Additionally chrome requires minor flag settings.