var timeout	= 0;
var closetimer	= 0;
var ddmenuitem	= 0;

// open hidden layer
function mopen(id)
{	
	// cancel close timer
	mcancelclosetime();

	// close old layer
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

	// get new layer and show it
	ddmenuitem = document.getElementById(id);
	ddmenuitem.style.visibility = 'visible';

}
// close showed layer
function mclose()
{
	if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}

// go close timer
function mclosetime()
{
	closetimer = window.setTimeout(mclose, timeout);
}

// cancel close timer
function mcancelclosetime()
{
	if(closetimer)
	{
		window.clearTimeout(closetimer);
		closetimer = null;
	}
}

// close layer when click-out
document.onclick = mclose; 
	
	function f1()
	{
	document.getElementById("image1").src="images/btn_corprelo_over.gif";
	}
	function f2()
	{
	document.getElementById("image1").src="images/btn_corprelo.gif";
	}
	function f3()
	{
	document.getElementById("image2").src="images/btn_local_over.gif";
	}
	function f4()
	{
	document.getElementById("image2").src="images/btn_local.gif";
	}
	function f5()
	{
	document.getElementById("image3").src="images/btn_longdist_over.gif";
	}
	function f6()
	{
	document.getElementById("image3").src="images/btn_longdist.gif";
	}
	function f7()
	{
	document.getElementById("image4").src="images/btn_intl_over.gif";
	}
	function f8()
	{
	document.getElementById("image4").src="images/btn_intl.gif";
	}
	function f9()
	{
	document.getElementById("image5").src="images/btn_storage_over.gif";
	}
	function f10()
	{
	document.getElementById("image5").src="images/btn_storage.gif";
	}
	function f11()
	{
	document.getElementById("image6").src="images/btn_home_over.gif";
	}
	function f12()
	{
	document.getElementById("image6").src="images/btn_home.gif";
	}