Only allow droppable object in certain container???

Only allow droppable object in certain container???

Hi People,
 
Here is my code which allows me to drag a div on to another div. It then sets a they hidden variables (position) and does a post back to save those variables into an SQL database. My problem is the user can drag and drop the pointer anywhere on the screen and I only want them to be able to drop into the divPhoto container.
<head runat="server">
    <title></title>
    <link href="CSS/Default.css" rel="stylesheet" type="text/css"/>
    <script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jqueryui/1.9.2/jquery-ui.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            $(".divPointer").draggable({
                stop: function (event, ui) {
                    var Stoppos = $(this).position();
                    var item_id = event.srcElement.id;
                    var bg_url = $(this).css('background-image');
                    $("input[id*='inpLeft']").val(Stoppos.left);
                    $("input[id*='inpTop']").val(Stoppos.top);
                    $("input[id*='inpImageUrl']").val(bg_url);
                    $($get("imgSave")).click();
                }
            });
        });
    </script>
</head>
<body>
    <form id="form1" runat="server">
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <input id="inpImageUrl" type="hidden" runat="server" />
        <input id="inpLeft" type="hidden" runat="server" />
        <input id="inpTop" type="hidden" runat="server" />
        <div>
            <asp:Label ID="Label1" runat="server" cssclass="lblPhotoTitle" Text="Photo 1"></asp:Label>
            <asp:Label ID="Label2" runat="server" cssclass="lblKPITitle" Text="Key Inspection Points"></asp:Label>
            <div id="divPhoto" runat="server">
                <asp:ImageButton ID="imgSave" runat="server" style="width:0px; height:0px;"/>
                <asp:ImageButton ID="imgPhoto" runat="server" CssClass="imgPhoto" ImageUrl="" />
                <div id="divPhotoToolbar" runat="server">
                    <asp:FileUpload ID="fupPhotos" runat="server" CssClass="fupPhotos" />
                    <asp:ImageButton ID="imgPrevious" runat="server" CssClass="imgPrevious" ImageUrl="~/Images/Left_Arrow.png" />           
                    <asp:Button ID="butUpload" runat="server" cssclass="butUpload" OnClick="butUpload_Click" Text="Upload" />
                    <asp:ImageButton ID="imgNext" runat="server" CssClass="imgNext" ImageUrl="~/Images/right.png" />
                </div>
            </div>
            <div id="divKPIs" runat="server">            
                <asp:ImageButton ID="imgLeft1" runat="server" CssClass="imgLeft" ImageUrl="e:ack.png" />
                <div id="divPointer1" runat="server" class="divPointer" style="background-image:url('Pointers/Blob-1 W.gif'); background-repeat: no-repeat;"></div>
                <asp:ImageButton ID="imgRight1" runat="server" CssClass="imgRight" ImageUrl="e: orward.png" />
                <asp:TextBox ID="txtKPI1" runat="server" CssClass="txtKPI" Enabled="False"></asp:TextBox>
            </div>
        </div>
    </form>
</body>
















































 
Thanks for any help,
 
Jiggy!