var nav_interval = "stop";
var nav_direction = 1;
var nav_position = -6;

function nav_show()
	{
	nav_direction = 1;
	if(nav_interval == "stop")
		{
		nav_interval = setInterval("nav_animation()",50);
		}
	}
function nav_hide()
	{
	nav_direction = -1;
	if(nav_interval == "stop")
		{
		nav_interval = setInterval("nav_animation()",50);
		}
	}

function nav_animation()
	{
	if( ((nav_direction==1)&&(nav_position == 0)) || ((nav_direction==-1)&&(nav_position == -6)) )
		{
		clearInterval(nav_interval);
		nav_interval = "stop";
		}
	else
		{
		nav_position += nav_direction;
		}
	document.getElementById("nav").style.top = nav_position + "em";

	}

if(document.getElementById)
	{
	document.getElementById("nav").onmouseover = nav_show;
	document.getElementById("nav").onmouseout = nav_hide;
	}