function showlogin(opt) {
	var ns4=document.layers
	var ie4=document.all
	var ns6=document.getElementById&&!document.all
	logbox=ns6? document.getElementById("login") : document.all.login	
	if (ie4||ns6)
	{ 
		if (opt==-1) {
			logbox.style.visibility="visible";
		} else {
		  logbox.style.visibility="hidden";
		}	
	}
	else if (ns4)
	{ 
	  if (opt==-1) {
			document.logbox.visibility="show";
		} else {	
			document.logbox.visibility="hide";
		}	
	}
}