var on = 0;

menus = new Object();

menus.about = new Object();
menus.about.x = 0;
menus.about.y = 30;

menus.help = new Object();
menus.help.x = menus['about'].x + 74;
menus.help.y = menus['about'].y;

menus.db = new Object();
menus.db.x = menus['help'].x + 74;
menus.db.y = menus['help'].y;

menus.search = new Object();
menus.search.x = menus['db'].x + 72;
menus.search.y = menus['db'].y;

function get_layer_style(name)
{
	if( document.layers )
	{
		window.alert("layers");
		return false;
	}

	else if( document.getElementById )
	{
		return document.getElementById(name);
	}

	else if( document.all )
	{
		return document.all[name];
	}

	else if( document[name] )
	{
		return document[name];
	}
	else
	{
		window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (menu layers)");
	}
	return false;
}


function hide_layer(name)
{
	var ref = get_layer_style(name);

	if ( ! ref ) return;

	if ( ref.style ) ref.style.visibility = 'hidden';
	else
	{
                if( ref.visibility )
			ref.visibility = 'hide';
		else
			window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (visibility hide)");
	}
}


function show_layer(name)
{
	var ref = get_layer_style(name);

	if ( ! ref ) return;

	if ( ref.style ) ref.style.visibility = 'visible';
	else
	{
                if( ref.visibility )
			ref.visibility = 'show';
		else
			window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (visibility show)");
	}
}


function move_layer_to(name, x, y)
{
	var ref = get_layer_style(name);

	if ( ! ref ) return;

	if ( ref.style )
	{
		ref.style.top  = y + 'px';
		ref.style.left = x + 'px';
	}
	else
	{
		if ( ref.top )
		{
			ref.top  = y + 'px';
			ref.left = x + 'px';
		}
		else
			window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (top, left)");
	}
}


function showmenu_slow(id)
{
	_showmenu(id, 250);
}

function showmenu(id)
{
	_showmenu(id, 0);
}

function _showmenu(id, delay)
{
	if ( document[id] )
	{
		document[id].src = 'pict/_' + id + '1.gif';
		on = id;
	}
	else
	{
		if ( document.images[id] )
		{
			document.images[id].src = 'pict/_' + id + '1.gif';
			on = id;
		}
		else
			window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (images id)");
	}


	var name = 'menu_' + id;

	if ( menus[id] )
		move_layer_to(name, menus[id].x, menus[id].y);
	else
		return;

	if ( delay )
		menutimer = window.setTimeout("show_layer('" + name + "')", delay);
	else
		show_layer(name);
}


function hidemenu()
{
	if ( window.menutimer )
	{
		clearTimeout(menutimer);
	}

	if (!on)
	{
		return;
	}

	if ( document[on] )
		document[on].src = 'pict/_' + on + '.gif';
	else
	{
		if ( document.images[on] )
			document.images[on].src = 'pict/_' + on + '.gif';
		else
			window.alert("Nefunguje? Kontaktujte isis@ucl.cas.cz. (images id)");
	}


	hide_layer('menu_' + on)
	on = 0;
}


function togglemenu(name)
{
	if (! on)
	{
		showmenu_slow(name);
		return;
	}

	if (on == name)
	{
		hidemenu();
		return;
	}

	hidemenu();
	showmenu_slow(name);
}