I would like to call JavaScript functions to show/hide a loading animation when a DropDownList is changed in an UpdatePanel.
Here is the DopDownList in an UpdatePanel
<asp:UpdatePanel ID="UpdatePanel4" runat="server">
<ContentTemplate>
<asp:DropDownList ID="ddl_size" runat="server" OnSelectedIndexChanged="ddl_size_SelectedIndexChanged" AutoPostBack="true">/asp:DropDownList>
...
Here are the JavaScript functions I want to call
function ShowLoadingAnimation() { ... }
function HideLoadingAnimation() { ... }
Do I use triggers? How do I use it? Thanks in advance.