Thanks to aNieto2k (in Spanish about Flash Player version detection with Javascript) I’ve found a web page that tells you not only if you got Flash Player plugin installed but also which version.
I use to browse the Internet with Firefofox and so easy to type in the URL bar:
about:plugins
that I forget it’s no easy on different browsers, so that web page has come useful ’cause it doesn’t matter which browser you use ’cause it detecs quite accurately your installed version. Good job.