如何使用jQuery Draggable和Droppable实现拖拽功能

<div id='draggableDiv' class="ui-widget-content">
        中间拖拽容器元素
    </div>
    <script type="text/javascript">
        $("#draggableDiv").draggable({
            containment: "parent",
            drag: function (event, ui) { console.log("拖拽中"); },
            stop: function () { console.log("拖拽结束"); }
        });
    </script>

var clickElement = null; $(".threepanels .ptreelist").bind("mousedown",function (event) {
//获取当前mousedown元素的内容
var itemContent = $(this).html(); var draggableDiv = $("#draggableDiv");
$(draggableDiv).css({ "display": "block", "height": 0 });
//将点击的元素内容复制
clickElement = $(this).clone();
var currentdiv = $(this).offset(); $(draggableDiv).css({ "top": currentdiv.top, "left": currentdiv.left }); draggableDiv.trigger(event);
//取消默认行为 return false; });
$("#draggableDiv").mouseup(function (event) { $(this).css({ "height": "0" }); });
//拖动元素时鼠标的位置
var dragDivLeft = 0;
var dragDivTop = 0;
$("#draggableDiv").draggable({ containment: "parent", drag: function (event, ui) { $("#draggableDiv").css({ "width": "260px", "height": "22px" });
    $("#draggableDiv").append(clickElement);
    var closeTop = $(".closeBar").offset().top;
    dragDivLeft = event.target.offsetLeft;
    dragDivTop = event.target.offsetTop; },
    stop: function () {
        //拖拽结束，将拖拽容器内容清空
        $("#draggableDiv").html("");
        $("#draggableDiv").css({"height":"0"}); }
});