How to drop and object on grid?

It is bound to my mouse, then i click and it have to fill a place on the grid. How?

do you mean how to make an object snap to grid?

if so you can do:

set object x to round(object.x/8)*8

and replace 8 with whatever gridsize you want, or a variable

do the same for Y

if your hotspot is in the top left corner, use int() instead of round()

Done it, thanks. Also boolean variable solved lots of issues.