window_mouse_get_y();
Returns: Real
With this function you can get the y position of the mouse cursor (in pixels) within the browser if it is an HTML5 game or within the display if it is a Windows, Ubuntu (Linux) or MacOS game.
NOTE: For regular mouse functions see the section on Mouse Input.
wy = window_mouse_get_y();
The above code stores the current y axis window position of the mouse in the variable "wy".