Want to be able to Close a Modal Popup when Clicked Outside of it

I have a modal popup extender and a panel inside of an update panel. I do have a Close button which I bind with the Cancel ControlId. I however, would like to be able to click outside of my modal/panel to close the panel. (instead of using the close button).
I tried a couple things and a plugin clickoutside. Nothing seems to help. Any help or advice is much appreciated.

<asp:content id="Content3" contentplaceholderid="rightNavigation" runat="server">

<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>

<div id="mls_title" class="MLS_Title">

<asp:Label ID="lblTitle1" Text="Tasks" runat="server" class="MLS_titleLbl" /><br />

</div>

<asp:UpdatePanel ID="pnlMap" runat="server">

<ContentTemplate>

<div>

<asp:Button ID="btnMap" runat="server" Text="MAP" CausesValidation="false" CssClass="btnMap" />

<ajax:ModalPopupExtender

ID="ModalPopupExtender1"

runat="server"

TargetControlID="btnMap"

PopupControlID="panel1"

PopupDragHandleControlID="PopupHeader"

Drag="true"

BackgroundCssClass="ModalPopupBG">

</ajax:ModalPopupExtender>

<asp:Panel ID="panel1" runat="server">

<div class="popup_large">

<asp:Label ID="Label7" Text="Floor Plan" runat="server" stle="float:left"></asp:Label>

<asp:ImageButton ID="ImageButton1" runat="server" ToolTip="No" ImageUrl="~/Images/no.png" Style="float: right; margin-right: 20px" />

<br />

<asp:ImageButton ID="img" runat="server" Height="30em" Width="45em" />

</div>

</asp:Panel>

</div>

</ContentTemplate>

</asp:UpdatePanel>

 
C#
 

<AjaxToolKit:ModalPopupExtender .... BackgroundCssClass="jsMpeBackground" />

JavaScript (using jQuery)

jQuery('.jsMpeBackground').click(function () {

var id = jQuery(this).attr('id').replace('_backgroundElement', '');

$find(id).hide();

});

Here is a link to an example that adds to the background onclick to close the modal:

http://forums.asp.net/t/1528820.aspx

Copied the key bits here for reference:
 

function pageLoad() {

var mpe = $find("MPE");

mpe.add_shown(onShown);

}

function onShown() {

var background = $find("MPE")._backgroundElement;

background.onclick = function() { $find("MPE").hide(); }

}

<AjaxToolKit:ModalPopupExtender ID="mdlPopup" BehaviorID="MPE" runat="server"

TargetControlID="btnShowPopup" PopupControlID="pnlPopup"

CancelControlID="btnClose" BackgroundCssClass="modalBackground" />

Use ModalPopupExtender without having to set TargetControlID?

The TargetControlID of 'ModalPopupExtender1' is not valid. The value cannot be null or empty. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: The TargetControlID of 'ModalPopupExtender1' is not valid. The value cannot be null or empty.