function popup(url,width,height,scrollbars)
{
	top.name = 'main_window'; 
	var popup = window.open(url,'radio','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars='+scrollbars+',resizable=no,width='+width+',height='+height+',left=100,top=100') 
	if (navigator.appName.substring(0,8) == 'Netscape') 
	{ 
		popup.location = url; 
		popup.opener = self; 
	} 
}