Hide ASP.Net AJAX CalendarExtender Control when ESC Key is pressed in browser

Here's the sample for you where I am hiding Calendar on ESC press

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <asp:TextBox ID="TextBox1" runat="server" onkeyup="KeyUp(event.keyCode)"></asp:TextBox>
    <cc1:CalendarExtender ID="CalendarExtender1" runat="server" TargetControlID="TextBox1"
        Format="yyyy-MM-dd" PopupButtonID="ImageButton1">
    </cc1:CalendarExtender>
    <asp:ImageButton ID="ImageButton1" runat="server" ImageUrl = "~/images/calendar.png"/>
    <script type="text/javascript" language="javascript">
        function KeyUp(keyCode) {
            if (keyCode == 27) {
                $find("<%=CalendarExtender1.ClientID %>").hide();
            }
        }
    </script>