function roll(base,menu,status)
   {
     eval("document.menu_"+menu+".src='"+base+"comuni/img/menu_"+menu+"_"+status+".gif';");
   }

   function calc_left (w) {
   	var left = (screen.availWidth / 2) - (w / 2);
   	return (left);
   }
   
   function calc_top (h) {
   	var top = (screen.availHeight / 2) - (h / 2);
   	return (top);
   }
   
   function open_popup (url, w, h, scrollbar,toolbar,status,menubar,id) {
    //alert(scrollbar)
    if(!scrollbar){scrollbar = 'no'}
    if(!toolbar){toolbar = 'no'}
    if(!status){status = 'no'}
    if(!menubar){menubar = 'no'}
    if(!id){id = ''}
    
   	var top = calc_top (h);
   	var left = calc_left (w);
   
   	popup = window.open (url,id,'width='+w+',height='+h+',left='+left+',top='+top+',screenX='+left+',screenY='+top+'status='+status+', menubar='+menubar+', toolbar='+toolbar+', scrollbars='+scrollbar);
   	popup.focus();
   }