// change style for navigation link to 'current' page
function setNavigation(){
	var bodyTag = document.getElementsByTagName('BODY')[0]
	var navigationId = bodyTag.id + '-navigation'
	var currentNavigation = document.getElementById(navigationId)
	if (currentNavigation) {
		var currentImageSource = "/images/"+navigationId+"_current.jpg"
		currentNavigation.style.backgroundImage = "url("+currentImageSource+")"
	}
}

// hook up setNavigation() unobtrusively
addEvent(window, 'load', setNavigation)