function menushow(menunum)
  {
	var currentmenu = document.getElementById("drop" + menunum);
	var currentico = document.getElementById("ico" + menunum);
	if (currentmenu.style.display == 'block') 
	{
		currentmenu.style.display = 'none';
		currentico.style.backgroundImage = "url(./pics/plus.gif)";
		currentico.style.backgroundRepeat = "no-repeat";
	}
	else 
	{
		currentmenu.style.display = 'block'; 
		currentico.style.backgroundImage = "url(./pics/minus.gif)";
		currentico.style.backgroundRepeat = "no-repeat";
	}
  }