ActionScript for Flash MX: The Definitive Guide, 2nd Edition By Colin Moock
Chapter 18. ActionScript Language Reference
Button._y Property
Flash 6
vertical location of the button, in pixels
read/write
theButton._y
Description
The floating-point _y property indicates the vertical position of theButton's registration point. It is measured relative to one of two possible coordinate spaces:
If theButton resides on the main timeline, _y is measured relative to the Stage's top edge.
If theButton resides on a movie clip instance's timeline, _y is measured relative to the registration point of that parent instance.
The _y property (along with all vertical coordinates in Flash) increases downward and decreases upward the opposite of the Cartesian coordinate system.
Button._y is directly analogous to MovieClip._y; see that property entry for full details.
Example
// Place quit_btn directly on its parent's registration point. quit_btn._x = 0; quit_btn._y = 0;
