if (window.addEventListener){
	window.addEventListener("load", set_banner_value, false);
}
else{
	if (window.attachEvent) {
		window.attachEvent("onload", set_banner_value);
	}
	else{ 
		if (document.getElementById){
			window.onload=set_banner_value;
		}
	}
}

function set_banner_value ()
{
	var banner_cookie = get_cookie("hidden_banner");
	if (banner_cookie) {
		var banner = document.getElementById('banner_right').style;
	
		if (banner_cookie == "true") {
			//if (banner.visibility != hidden) //check of de banner al verborgen is
				hideBanner();
		}
		else {
			//if (banner.visibility != visible) //check of de banner al getoond wordt
				showBanner();
		}
	}
}

function get_cookie (cookie_name)
{
  var results = document.cookie.match ('(^|;) ?' + cookie_name + '=([^;]*)(;|$)');

  if (results)
    return (unescape (results[2]));
  else
    return null;
}

function get_expire_date()
{
	var expire_date = new Date();
	expire_date.setTime(expire_date.getTime()+(365*24*60*60*1000));	
	return "; expires="+expire_date.toGMTString();
}
		
function hideBanner ()
{
	var banner = document.getElementById('banner_right').style;
	banner.visibility = 'hidden';	
	document.cookie = "hidden_banner=true"+get_expire_date();
	var showBanner = document.getElementById('showBanner');
	showBanner.src = "images/open_banner_right.gif";			
}

function showBanner ()
{
	var banner = document.getElementById('banner_right').style;
	banner.visibility = 'visible';
	document.cookie = "hidden_banner=false"+get_expire_date();
	var showBanner = document.getElementById('showBanner');
	showBanner.src = "images/close_banner_right.gif";
}

function switchBanner ()
{
	var banner = document.getElementById('banner_right').style;
	if (banner.visibility == 'hidden') {
		showBanner();
	}
	else {
		hideBanner();
	}
}