win2 = window.open("popup_choose_template.html", "Window2", "width=310,height=600,scrollbars=yes");

$( "#dialog-confirm" ).dialog({
    height:140,
    modal: true,
    buttons: {
        "Ok": function() {
            $( this ).dialog( "close" );
        },
        Cancel: function() {
            $( this ).dialog( "close" );
        }
    }
});

<div id="blackout" style="position:fixed; width:100%; height:100%; z-index:100; background-color:black; opacity:0.5;"></div>