https://arxiv.org/static/browse/0.3.4/js/accordion.js

1// vanilla accordion script. no jquery, dependencies.
2var jsaccordion = {
3  init : function (target) {
4  // initialize the accordion
5    var headers = document.querySelectorAll("#" + target + " .toggle-control");
6    if (headers.length > 0) { for (var head of headers) {
7      head.addEventListener("click", jsaccordion.select);
8    }}
9  },
10  select : function () {
11  // fired when user clicks on a header
12    var contents = this.nextElementSibling;
13    contents.classList.toggle("open");
14    var contents = this;
15    contents.classList.toggle("open");
16  }
17};
18// runs on page load
19window.addEventListener('load', function(){
20  jsaccordion.init("toggle-container");
21});