var springads = new Object();
var today = new Date(); 
var zero_date = new Date(0,0,0); 
today.setTime(today.getTime() - zero_date.getTime()); 
var cookie_expire_date = new Date(today.getTime() + (8 * 7 * 86400000)); 
springads['odd'] = new Array();
springads['even'] = new Array();

function changeSpringAd(){
	var c = Get_Cookie('springad');
	for(var i=0; i< springads['even'].length;i++){
		if(springads['even'][i]){
			springads['even'][i].style.display = (c=='even') ? 'block':"none";
			springads['even'][i].style.visibility = (c=='even') ? 'visible':'hidden';
		}
	}
	for(var i=0; i< springads['odd'].length;i++){
		if(springads['odd'][i]){
			springads['odd'][i].style.display = (c=='odd') ? 'block':"none";
			springads['odd'][i].style.visibility = (c=='odd') ? 'visible':'hidden';
		}
	}
}

function initspringad() {
	var divs = document.getElementsByTagName('DIV');
	var d='even';
	var a=0;
	for(var i=0; i< divs.length;i++){
		if(divs[i].className=='springad'){
			d = (d=='even')?'odd':'even';
			if( typeof divs[i] != 'undefined' ) springads[d][a] = divs[i];
			a++;
 		}
	}
	var c = Get_Cookie('springad');
	if(c=='odd'){ 
		Set_Cookie('springad','even',cookie_expire_date,'/',false);
	} else {
		Set_Cookie('springad','odd',cookie_expire_date,'/',false);
	}
	changeSpringAd();
}

function Get_Cookie(name) { 
	var start = document.cookie.indexOf(name+"="); 
	var len = start+name.length+1; 
	if ((!start) && (name != document.cookie.substring(0,name.length))) return null; 
	if (start == -1) return null; 
	var end = document.cookie.indexOf(";",len); 
	if (end == -1) end = document.cookie.length; 
	return unescape(document.cookie.substring(len,end)); 
} 

function Set_Cookie(name,value,expires,path,domain,secure) { 
	var cookieString = name + "=" +escape(value) + 
		( (expires) ? ";expires=" + expires.toGMTString() : "") + 
		( (path) ? ";path=" + path : "") + 
		( (domain) ? ";domain=" + domain : "") + 
		( (secure) ? ";secure" : ""); 
	document.cookie = cookieString; 
}

window.onload = initspringad;