var refer1=true;
function menu1() 
{
	if (refer1) 
	{
		document.all.contents1.style.visibility="visible";
		refer1=false;
	}
	else 
	{
		document.all.contents1.style.visibility="hidden";
		refer1=true;
	}
}
var refer2=true;
function menu2() 
{
	if (refer2) 
	{
		document.all.contents2.style.visibility="visible";
		refer2=false;
	}
	else 
	{
		document.all.contents2.style.visibility="hidden";
		refer2=true;
	}
}
var refer3=true;
function menu3() 
{
	if (refer3) 
	{
		document.all.contents3.style.visibility="visible";
		refer3=false;
	}
	else 
	{
		document.all.contents3.style.visibility="hidden";
		refer3=true;
	}
}