function Menu(idMenu) 
{ 
    var thisMenu;

    if (navigator.appName == "Netscape") 
	{
		thisMenu = document.getElementById(idMenu).style;
	}
	else
	{
		if (document.all) 
		{
			thisMenu = eval("document.all." + idMenu + ".style")
    	}
		else
		{
            return true;
    	}
	}

	if (thisMenu.display == "block") 
	{
		thisMenu.display = "none";
	}
	else
	{
		thisMenu.display = "block";
	}
}