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