var lastunderscoresource = null;
var lastclicked = document.getElementById("underscore_1"); 

function showHoverLink(element)
{
  	bits = element.id.split( "_" );

	currentunderscore = document.getElementById("underscore_" + bits[1]); 
	lastunderscoresource = currentunderscore.src;
	currentunderscore.src = "/media/images/nav/hover.gif";
}

function showOffLink(element)
{
  	bits = element.id.split( "_" );

	document.getElementById("underscore_" + bits[1]).src = lastunderscoresource; 
}

function showOnLink(element)
{	
	lastclicked.src = "/media/images/nav/off.gif";
	
  	bits = element.id.split( "_" );
		
	lastclicked = document.getElementById("underscore_" + bits[1]); 
	
	document.getElementById("underscore_" + bits[1]).src = "/media/images/nav/on.gif";
	lastunderscoresource = document.getElementById("underscore_" + bits[1]).src;
}