function extractUrlParams() {
    var t = location.search.substring(1).split('&');
    var f = [];
    for (var i = 0; i < t.length; i++) {
        var x = t[i].split('=');
        f[x[0]] = x[1];
    }
    return f;
}

function afficherTabDefaut() {
    params = extractUrlParams();
    for (paramName in params)
        if (paramName == "tab")
        afficherTab(params[paramName]);
}