gdr-site/static/main.js

window.onload = () => {
  let buttons = document.querySelectorAll(".showmore");
  let toggles = {};
  for (let b of buttons) {
    toggles[b] = false;
    b.onclick = (elem, thing) => {
      for (let i of b.parentElement.querySelectorAll(".item")) {
        if (toggles[b]) {
          i.style.display = 'none';
        } else {
          i.style.display = 'block';
        }
      }
      toggles[b] = !toggles[b];
    };
  }
};