Close bootstrap modal by clicking the browser back button

$('div.modal').on('show.bs.modal', function() {
    var modal = this;
    var hash = modal.id;
    window.location.hash = hash;
    window.onhashchange = function() {
        if (!location.hash){
            $(modal).modal('hide');
        }
    }
});

$('div.modal').on('hide', function() {
    var hash = this.id;
    history.pushState('', document.title, window.location.pathname);
});