function change_visibility(nom, index){
    if(document.getElementById('moins' + nom).style.display == 'none')
    {
        reveler(nom, index);
    }
    else
    {
        masquer(nom, index);
    }
}

function masquer(nom, index){
    for(var i in index)
    {
        if(document.getElementById('cat' + index[i]))
        {
            document.getElementById('cat' + index[i]).style.display = 'none';
        }
    }

    document.getElementById('moins' + nom).style.display = 'none';
    document.getElementById('plus' + nom).style.display = 'inline';

    var date = new Date;

    date.setFullYear(date.getFullYear() + 1);
    EcrireCookie(nom, '1', date, '/');
}

function reveler(nom, index){
    for(var i in index)
    {
        if(document.getElementById('cat' + index[i]))
        {
            document.getElementById('cat' + index[i]).style.display = (document.all && !opera) ? 'block' : 'table-row';
        }
    }

    document.getElementById('moins' + nom).style.display = 'inline';
    document.getElementById('plus' + nom).style.display = 'none';

    EffaceCookie(nom);
}

function EcrireCookie(nom, valeur){
    var argv = EcrireCookie.arguments;
    var argc = EcrireCookie.arguments.length;
    var expires = (argc > 2) ? argv[2] : null;
    var path = (argc > 3) ? argv[3] : null;
    var domain = (argc > 4) ? argv[4] : null;
    var secure = (argc > 5) ? argv[5] : false;

    document.cookie = nom + '=' + escape(valeur) + ((expires == null) ? '' : ('; expires=' + expires.toGMTString())) + ((path == null) ? '' : ('; path=' + path)) + ((domain == null) ? '' : ('; domain=' + domain)) + ((secure == true) ? '; secure' : '');
}

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 '';
}

function EffaceCookie(nom){
    var date = new Date;

    date.setFullYear(date.getFullYear() - 1);

    EcrireCookie(nom, null, date, '/');
}