autoScroll
autoScroll : Number
How fast to scroll the container element when autoScroll is true.
Details
Number - To enable auto-scrolling when a Draggable is dragged within 40px of an edge of a scrollable container, set autoScroll to a non-zero value, where 1 is normal speed, 2 is double-speed, etc. (you can use any number). For a more intuitive or natural feel, it will scroll faster as the mouse/touch gets closer to the edge. The default value is 0 (no auto-scrolling).