IPhone 6 Parallax Scrolling Effect Full width slider background-position issue

div {   
    background-image: url(images/welcome.jpg);
    background-attachment: fixed;
    background-position: top center;
    background-size: cover;
    height: 100vh;
    top: 0;
    left: 0;
    min-width: 100%;
    min-height: 100%;
}

div {   
    background-image: url(images/welcome.jpg);
    background-attachment: scroll;
    background-position: top center;
    background-size: cover;
    height: 100vh;
    top: 0;
    left: 0;
    min-width: 100%;
    min-height: 100%;
}