var compatibility = null;

            function pop(url, vwidth, vheight, vscroll, vresize)

            {

                    if (compatibility && !compatibility.closed)

                            compatibility.location.href = url;

                    else

                            compatibility = window.open(url,'compatibility','height='+vheight+',width='+vwidth+',scrollbars='+vscroll+',resizable='+vresize+',toolbar=no');

                    if (window.focus) compatibility.focus();

            }