function open_NW(adr,winName,screenwidth,screenheight) {
     screenwidth+=20;screenheight+=20;
     if (screenwidth<(screen.availWidth/2)) {
        xPos = screen.availWidth/2 - screenwidth -10;
     } else {
        xPos = screen.availWidth - screenwidth -10;
     }
     if (screenheight<(screen.availHeight/2)) {
        yPos = screen.availHeight/2 - screenheight -10;
     } else {
        yPos = screen.availHeight - screenheight -10;
     }
     var NW = window.open(adr,winName,"toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,copyhistory=no,width="+screenwidth+",height="+screenheight+",screenX="+xPos+",screenY="+yPos+",left="+xPos+",top="+yPos);
     NW.focus();
}