physics body moves in browser but not on mac or ios

Question

i was trying to move the physics body by changing its coordinate in scheduler and i used this code. if i run this code in browser it will work but after js binding it doesn't work on mac or ios. Physics body doesn't move at all on these devices

init: function{
 var mass = 1;    
var width = 1, height = 1;
this.playerBody = new cp.Body(mass , cp.momentForBox(mass, width, height));
this.space.addBody(this.playerBody);

this.schedule(this.move);
},
move: function(dt){
this.space.step(dt);
this.playerBody.getPos().x += 2 * dt;
this.playerBody.getPos().y += 2 * dt;
}

Answer 1

after adding few lines my player started to move in mac

init: function{
var mass = 1;    
var width = 1, height = 1;
this.playerBody = new cp.Body(mass , cp.momentForBox(mass, width, height));
this.space.addBody(this.playerBody);

this.schedule(this.move);
},
move: function(dt){
this.space.step(dt);
var a = this.playerBody.local2World(this.playerBody.p);
a.y += 2 * dt;
a.x += 2 * dt ;
a = this.playerBody.world2Local(a);
this.playerBody.p = a;
}

but i don't have explanation of this code