Customize Accordion expand or collapse animation behavior

19 Dec 20223 minutes to read

Accordion component supports customizing the expand or collapse animation action behavior. You can manually adjust the expand animation action that occurs after the collapse animation operation is performed on the already expanded pane, When the expand icons are clicked.

By default, the Accordion component pane is expanded or collapsed, while clicking the expand or collapse icon. It is not affected on already expanded pane.

The following sample demonstrates, how to expand the collapsed Accordion item after collapse animation is performed on the expanded Accordion item using created, expanding, and expanded event. In the Expanding event, get the previously expanded item index and prevent the expanding behavior using args.cancel option. Expand the Accordion item dynamically based on the specified index value using the expandItem public method and expanded event.

@using Syncfusion.EJ2.Navigations;

<ejs-accordion id="defaultAccordion" expandMode="Single" created="created" expanded="expanded" expanding="expanding">
        <e-accordion-accordionitem expanded="true" header="ASP.NET" content="Microsoft ASP.NET is a set of technologies in the Microsoft .NET Framework for building Web applications and XML Web services. ASP.NET pages execute on the server and generate markup such as HTML, WML, or XML that is sent to a desktop or mobile browser. ASP.NET pages use a compiled,event-driven programming model that improves performance and enables the separation of application logic and user interface."></e-accordion-accordionitem>
        <e-accordion-accordionitem header="ASP.NET MVC" content="The Model-View-Controller (MVC) architectural pattern separates an application into three main components: the model, the view, and the controller. The ASP.NET MVC framework provides an alternative to the ASP.NET Web Forms pattern for creating Web applications. The ASP.NET MVC framework is a lightweight, highly testable presentation framework that (as with Web Forms-based applications) is integrated with existing ASP.NET features, such as master pages and membership-based authentication."></e-accordion-accordionitem>
        <e-accordion-accordionitem header="JavaScript" content="JavaScript (JS) is an interpreted computer programming language.It was originally implemented as part of web browsers so that client-side scripts could interact with the user, control the browser, communicate asynchronously, and alter the document content that was displayed.More recently, however, it has become common in both game development and the creation of desktop applications."></e-accordion-accordionitem>

    var initialLoad = true;
    var isCollapsed = false;
    var expandIndex;
    var tabEle = document.getElementById("defaultAccordion");
    function expanding(e) {
        if (e.isExpanded && !initialLoad && !isCollapsed) {
            e.cancel = true;
            expandIndex = tabEle.ej2_instances[0].items.indexOf(e.item);
            isCollapsed = true;
    function expanded(e) {
        if (!e.isExpanded && !initialLoad && isCollapsed) {
            tabEle.ej2_instances[0].expandItem(true, expandIndex);
            isCollapsed = false;
    function created(e) {
        initialLoad = false;

Customize Accordion expand or collapse animation behavior


View Sample in GitHub.