How to change background Opacity when bootstrap modal is open

Question

I am using bootstrap modal. When modal is open background content opacity is not changed by default. I tried changing in js using

function showModal() {
doc         


        

Answer 1

Just in case someone is using Bootstrap 4. It seems we can no longer use .modal-backdrop.in, but must now use .modal-backdrop.show. Fade effect preserved.

.modal-backdrop.show {
    opacity: 0.7;
}