Well, Chrome is hinting to you that Silverlight isn't secure. From what I've heard, even Microsoft is giving up on Silverlight.
Firefox is directly telling you that Java in the browser isn't secure. I believe Firefox. However, if you choose to ignore the advice, I guess there's probably a way to enable Java in Firefox.
(By the way, Adobe Flash Player is becoming insecure, too.)
Personally, I unplugged Java from my browser (actually, I completely uninstalled Java from my PC, although that wasn't really necessary), I uninstalled Silverlight, and, although I keep Flash Player updated, I keep it disabled unless I really, really need to use it.
FWIW, my views are probably in the minority here, since most people just want to play the computer. (A small consolation is that V3 will not require the use of Java to play the computer; However, who knows when V3 will actually be pushed out for the masses?)
I recently started using Firefox because Chrome no longer supports Silverlight, which websites like Sky Go need to stream video content. Since installing Firefox, I can't use certain Java pop-up features on Chess.com such as the "Finish Game versus Computer" function. Instead of displaying the chessboard, I see a message saying "Activate Java". When I click this, a Firefox popup appears saying that the Java Development Toolkit (click-to-play) function is on Firefox's block list because it is known to be insecure. Anyone else have this problem? Can I just go ahead and enable it? Thanks