Add copyright message to copied text on website?

is there a way to add some sort of copyright message to copied text on a website? For example if somebody copies text via ctrl+c or right click+copy? I once saw this in a website...the reader copied some text and once it was pasted somewhere, it had an additional copyright message attache开发者_如何学Pythond.

Ideas?

Thanks :)

As @thirtydot pointed out, its good to use a service like http://www.tynt.com/ which removes the headache of scripting for you for intercepting copy+paste

Or refer to the following question How to detect right mouse click + paste using JavaScript? on stackoverflow.