var i,
                    acc = document.getElementsByClassName("accordion");
                for (i = 0; i < acc.length; i++)
                    acc[i].addEventListener("click", function () {
                        this.classList.toggle("active");
                        var e = this.nextElementSibling;
                        "block" === e.style.display ? (e.style.display = "none") : (e.style.display = "block");
                    });