How to put scroll bar only for modal-body?

 https://stackoverflow.com/questions/25874001/how-to-put-scroll-bar-only-for-modal-body

If you're only supporting IE 9 or higher, you can use this CSS that will smoothly scale to the size of the window. You may need to tweak the "200px" though, depending on the height of your header or footer.

.modal-body{
    max-height: calc(100vh - 200px);
    overflow-y: auto;
}