[KJS]

for me I would say something like

if(playerx>15&&playerx<17&&playery>20&&playery<22) {
//coding
}

I say this because like so the user doesn't have to be in 1 exact spot. they can be in anywere with in the box.

a 2x2 box.
of course the x and y will have to be edited to were you would like it but hopefully you get the idea