Close of Jquery Dialog not working for second time on click event of button which is in dynamic iframe dialog.

Question

 $('.Editcoupon').click(function() {
            var strRef = '';
            var strid = '';
            var strSelectedval = '';
            strRef = $(this).attr('ref');
            strid = $(this).attr('id');
            strqueryvalue = $(this).attr('ref').match(/Defaultcoupon=([0-9]+)/)[1];
            $("#Coupondialog-modal" + strid + strSelectedval).dialog("destroy")
            $("<div id='Coupondialog-modal" + strid + strqueryvalue + "' title='Click here to move' style='display:none;'><iframe src='" + strRef + "' width='740' height='457' frameborder='0' style='border:none;' id='vehicleIframe'></iframe></div>").appendTo('body');
            $("#Coupondialog-modal" + strid + strqueryvalue).dialog({
                width: 750,
                height: 502,
                resizable: false,
                autoOpen: false,
                //buttons: { "close": function() { $(this).dialog("close"); } },

                modal: true
            });
            $("#Coupondialog-modal" + strid + strqueryvalue).load();
            $("#Coupondialog-modal" + strid + strqueryvalue).dialog('open');

        });

the above is code to open a UI dialog of jquery where iframe is dynamically injected to body tag,which on click of a href tag ,for first time iam able to open dialog & close ,again when iam trying to open dialog ,close it using below code

window.parent.$("#Coupondialog-modalloadcoupons" + offerid+count ).dialog('close');

it is not closing the dialog ,which iam trying to call a client function on click of the Asp.net button event.

can any one please guide me ?