Yes, but not without installing something on client side.
You can install Google's Native Client and run a C++ app directly in a browser. But this is probably overkill.
You can also use a Javascript binding. I think I've seen one on github recently, you should check.
So, basically if you want to make a browser game, SFML is probably not the best choice. You'd better have a look at dedicated technologies such as Flash, HTML 5, etc. that can work out of the box.
