function displaySPTOGPOOverlay(){
	var cookiename = "sptogpo-overlay";
	var cookievalue = "viewed";
	
	if (document.cookie.length>0) {
		if (document.cookie.indexOf(cookiename) != -1) {
			//cookie has been set previously so do nothing
		}
		else {
			//set the cookie
			setSPTOGPOCookie(cookiename, cookievalue);	
		}
	}
	else{
		//set the cookie
		setSPTOGPOCookie(cookiename, cookievalue);	
	}
}

function setSPTOGPOCookie(cname, cvalue) {
	var exdate=new Date();
	exdate.setDate(exdate.getDate()+30);
	document.cookie= cname+ "=" +cvalue+ "; expires="+exdate.toUTCString()+ "; path=/;";	
	
	//show the overlay
	var ol = $("span[rel]").overlay({api: true, mask: '#000', top:0, fixed: false});
	setTimeout(function() {ol.load();}, 2000);	
}

function eraseSPTOGPOCookie() {
	var d = new Date();
    document.cookie = "sptogpo-overlay=1;expires=" + d.toGMTString() + "; path=/;";
}