var old;
var memold;

function pulldown(x)
	{
		if(!old)
			{
				old=memold;
			}

		if(old==x)
			{
				document.getElementById(x).style.visibility='hidden';
				old=x;
			}
			
		if(old!=x)
			{
				if(old)
					{
						document.getElementById(old).style.visibility='hidden';
					}
				document.getElementById(x).style.visibility='visible';
				old=x;
			}
		else
			{
				old="";
			}
	}

function do_check(x)
	{
		if(old && old!=x)
			{
				document.getElementById(old).style.visibility='hidden';
				document.getElementById(x).style.visibility='visible';
				old=x;
			}
	}

function do_out()
	{
		if(old)
			{
				document.getElementById(old).style.visibility='hidden';
			}
		
		memold=old;
		old="";
	}