/* display loading gif and hide webpage */
.modal {
    display:    none;
    position:   fixed;
    z-index:    1000;
    top:        0;
    left:       0;
    height:     100%;
    width:      100%;
    background: rgba( 255, 255, 255, .8)
                url('http://i.stack.imgur.com/FhHRx.gif')
                50% 50%
                no-repeat;
}

/* prevent scrollbar from display during load */
body.loading {
    overflow: hidden;
}

/* display the modal when loading class is added to body */
body.loading .modal {
    display: block;
}