jQuery/JS Common - Object Structures - positionConfig - at

Specifies the target element's side or corner where the overlay element should be positioned.

To set this property, use an object with the x and y fields. These fields specify the target element's horizontal and vertical sides, respectively. Alternatively, you can use a string shortcut from the accepted values list.

x

Specifies a position in the horizontal direction (for left, right, or center alignment).

y

Specifies a position in the vertical direction (for top, bottom, or center alignment).