function showExhibition(linkElem)
{
	$$('#content_container .exhibition_list a').invoke('removeClassName', 'current');
	linkElem.addClassName('current');
	
	$$('#content_container .content_scroller .images img').invoke('hide');
	$('exhibition_img_' + getQueryVariable('Exhibition', linkElem.href)).show();
	$$('#content_container .header_description .description').invoke('hide');
	$('exhibition_text_' + getQueryVariable('Exhibition', linkElem.href)).show();
	
	return false;
}

function getQueryVariable(variable, url) 
{
	if ( !url ) url = window.location.search;
	url = url.substring(url.indexOf('?') + 1);
	
	var vars = url.split("&");
	
	for ( var i = 0; i < vars.length; i++ ) {
		var pair = vars[i].split("=");
		if (pair[0] == variable) {
			return pair[1];
		}
	} 
	
	return null;
}

function highlightNav()
{
	
	var navLinkContainers = $$('#navigation_container li');
	
	for ( i = 0; i < navLinkContainers.length; i++ ) {
		navLink = navLinkContainers[i].select('a')[0];
		
		if ( window.location.toString().match(navLink.href) ) {
			navLinkContainers[i].addClassName('current');
		}
	}
	
	var subnavLinks = $$('#page_title_container h2 a');
	
	for ( i = 0; i < subnavLinks.length; i++ ) {
		if ( window.location.toString() == subnavLinks[i].href ) {
			subnavLinks[i].addClassName('current');
		}
	}
	
	var subnavLinks = $$('#content_container .exhibition_list a');
	
	for ( i = 0; i < subnavLinks.length; i++ ) {
		if ( window.location.toString() == subnavLinks[i].href ) {
			subnavLinks[i].addClassName('current');
		}
	}
	
}

function clickNavigationLink(eventObject)
{
	var clickedElement = eventObject.element();
	
	if ( clickedElement.tagName == 'LI' ) {
		var anchorElem = clickedElement.select('a');
		if ( anchorElem[0] ) {
			window.location = anchorElem[0].href;
		}
	}
}

function centerHeight()
{
	//var contentHeight = $('site_container').getHeight();
	var contentHeight = 721;
	var windowHeight = document.viewport.getHeight();
	
	if ( windowHeight == 0 && navigator.appName == "Microsoft Internet Explorer" ) {
		windowHeight = document.body.offsetHeight;
	}
	
	var posOffset = (windowHeight-contentHeight)/2;
	
	if ( posOffset > 0 ) {
		$('site_container').setStyle({top: posOffset + 'px'});
	}
	else {
		$('site_container').setStyle({top: '0px'});
	}
	
	$('body').setStyle({background: 'url(/site_images/background.jpg) no-repeat center ' + (posOffset-40) + 'px #666666'});
	
	//$('body').

}