var win = null;
function show_pop(w, h, url, scroll) {

        // open venster
        var strProperties = 'resizable,width=' + w + ',height=' + h;
        if (scroll) strProperties += ',scrollbars';
        if (!win) {
                win = window.open(url,'win',strProperties);
        } else {
                if (!win.closed) win.location.href = url;
                else win = window.open(url,'win',strProperties);
        }
        if (window.focus) win.focus();
}

function close_pop() {
        if (win) {
                if (!win.closed) {win.close(); win=null;}
        }
}