var acc = document.getElementsByClassName("accordion");
// var panel = document.getElementsByClassName("panel");
// alert(panel.length);
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;
    // alert("panel" + panel);
    if (panel.style.display === "block") {
        
      panel.style.display = "none";
    } else {
       
      panel.style.display = "block";
    }
  });
}
