Provide a correct complete code at the earliest..
Is that not too demanding? Show some courtesy atleast.
About your problem, if you can, try HTML5 Drag-drop feature. If not, then for reordering, easiest would be to change markup at runtime. Place the div chosen at a desired location. Something like:
$("#div4").insertAfter("#div2");
You need to use the even of reorder to use the above code.
Now, try out and post specific issue you get stuck. Do share what you try.