Scroll bar won't show on touch devices

I have this program using tabs jquery with a css overflow:scroll. It shows in PC but not in touch devices such as IPAD.

And what I just did is to add the css code below:

::-webkit-scrollbar {
    -webkit-appearance: none;
    width: 7px;
}
::-webkit-scrollbar-thumb {
    border-radius: 4px;
    background-color: rgba(0,0,0,.5);
    -webkit-box-shadow: 0 0 1px rgba(255,255,255,.5);
}
And it works.

Hope this helps!