var dragObject = null;
var u = 0;
var v = 0;
var x = 0;
var y = 0;

function initDragAndDrop()
{
	document.onmousemove = move;
	document.onmouseup = drop;
}

function drag(object)
{
	document.body.onselectstart = function ()
	{
		return false;
	};
	
	dragObject = object;
	u = x - dragObject.offsetLeft;
	v = y - dragObject.offsetTop;
	dragObject.drag();
}

function drop()
{
	if (dragObject)
	{
		dragObject.drop();
		dragObject = null;

		document.body.onselectstart = null;
	}
}

function move(event)
{
	x = window.event ? window.event.clientX : event.pageX;
	y = window.event ? window.event.clientY : event.pageY;

	if (dragObject)
	{
		dragObject.style.left = (x - u) + "px";
		dragObject.style.top = (y - v) + "px";
	}
}