body:before {
    content: 'Please turn on javascript';
    position: absolute;
    top: 50%;
    left: 50%;
    z-index: 2;
    width: 400px;
    height: 50px;
    margin-left: -200px;
    margin-top: -25px;
    background-color: #f00;
    color: #fff;
    border: 1px #ccc solid;
    font-weight: bold;
    text-align: center;
    padding-top: 20px;
}