Key press detection without focus

Fast question:

On a website, there is any way to detect when a keyboard key is pressed while the browser is minimized? or when you have the focus on another window?

For example, you open my website on Chrome, and you switch to Spotify for example, I need to detect if the user press a particular key that he previously binded.

I can imagine that's impossible with javascript because you have no focus on the browser, but, there is any way for it? Making a chrome extension maybe? with Java? Silverlight?

I just need to detect the user pressed the key, nothing else.

Thanks!