function writeCookie( nom, valeur, expires )
{
	document.cookie = nom + "=" + escape( valeur ) +
					  ((expires==null) ? "" : ("; expires="+expires.toGMTString()));
}

function getCookieVal( offset )
{
	var endstr = document.cookie.indexOf( ";", offset );
	if( endstr == -1 ) endstr = document.cookie.length;
	return unescape( document.cookie.substring( offset, endstr ) ); 
}

function readCookie( nom )
{
	var arg = nom + "=";
	var alen = arg.length;
	var clen = document.cookie.length;
	var i=0;
	while( i < clen )
	{
		var j = i + alen;
		if( document.cookie.substring( i, j ) == arg ) return getCookieVal( j );
		i=document.cookie.indexOf(" ",i)+1;
		if( i == 0 ) break;
	}
	return null;
}

function deleteCookie( nom )
{
	date=new Date;
	date.setFullYear( date.getFullYear()-1 );
	writeCookie( nom, null, date ); 
}