The write up assumes that your camera is set up for back button focus. (AE-L/AF-L button set to AF on.)
It should still work for shutter half press focus as well. With the AF set to AF-S, you half press the shutter to focus on an object.
Keeping the button half pressed, move back so that the object goes out of focus, and fully press the shutter. Nothing should happen.
Then, keeping the shutter fully pressed, move forward. As soon as the object comes back into focus,the shutter should fire.
Tried it on my D90 set up for back button focus and it works as described.