function file(fichier) {
    if (window.XMLHttpRequest)
        xhr_object = new XMLHttpRequest();
    else if (window.ActiveXObject)
        xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
    else
        return (false);
    xhr_object.open("GET", fichier, false);
    xhr_object.send(null);
    if (xhr_object.readyState == 4)
        return (xhr_object.responseText);
    else
        return (false);
}

function loadNewDoc(doc) {
    $("#mainContainer").html(file(doc));
    return false
}