How to show a javascript filled layer only once per session using a cookie

[Frituurman]

Hello,

I'm using a flying helicopter script on my site (http://www.deltaisis.nl), but I want the darn thing to show only once per session. since I'm a complete n00b.. what do I do to get this done? I've tried numerous things, but I kept getting errors.. All the code is easy accesseble (just look at the source)

Please help!

Kind regards,

Frituurman

[jscheuer1]

<script type="text/javascript">
//De variabele is hier helicopter. Komt in dit script terug. Variabele wordt overal gebruikt.
var helicopter
function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name) {
	createCookie(name,"",-1);
}
function pagestart(){
//Hier kun je de dimensies van de afbeelding invullen. Indien de helicopter 100px breed is en 50px hoog, vul dan de onderstaande maten in (hoogte - 13 / breedte - 12):
if(!readCookie('heli')){
 helicopter=new Chip("helicopter",87,38);
movechip("helicopter");
createCookie('heli',1);
}
}
if (window.addEventListener)
window.addEventListener("load", pagestart, false)
else if (window.attachEvent)
window.attachEvent("onload", pagestart)
else if (document.getElementById)
window.onload=pagestart
</script>