function initAccordion(accordionElem){
//when panel is clicked, handlePanelClick is called.
function handlePanelClick(event){
showPanel(event.currentTarget);
}
//Hide currentPanel and show new panel.
function showPanel(panel){
//Hide current one. First time it will be null.
var expandedPanel = document.getElementsByClassName(panel)
for(j=0; j< expandedPanel.length; j++){
if(expandedPanel[j].className == “panel active”){expandedPanel[j].className =’panel’}
}
//Show new one
this.className = “panel active”;
}
//var allPanelElems = accordionElem.querySelectorAll(“.panel”);
var allPanelElems = document.getElementsByClassName(“panel”);
for (var i = 0, len = allPanelElems.length; i < len; i++){
allPanelElems[i].addEventListener(“click”, handlePanelClick);
}
//By Default Show first panel
showPanel(allPanelElems[0])
}
initAccordion(document.getElementById(“accordion”));