var acc = document.getElementsByClassName('accordion')
var i

for (i = 0; i < acc.length; i++) {
  acc[i].addEventListener('click', function () {
    /* Toggle between adding and removing the "active" class,
    to highlight the button that controls the panel */
    this.classList.toggle('active')

    /* Toggle between hiding and showing the active panel */
    var panel = this.nextElementSibling
    if (panel.style.maxHeight) {
      panel.style.maxHeight = null
    } else {
      panel.style.maxHeight = panel.scrollHeight + 'px'
    }
  })
}