У меня следующий код ASP.NET:
<div id="pnlFiltros" class="card">
<asp:Panel ID="pnlFiltrosHeader" runat="server" CssClass="card-header bg-verdepetrobras text-white">
Filtros (<asp:Label ID="lblTextFiltros" runat="server" />)
</asp:Panel>
<asp:Panel ID="pnlFiltrosContent" runat="server" CssClass="card-body">
<div class="form-row">
<div class="form-group col-md-6">
<label>Chave / Nome</label>
<asp:TextBox ID="txtChaveNome" runat="server" CssClass="form-control" />
</div>
</div>
<div class="form-row">
<div class="form-group col-md-2">
<asp:Button ID="btPesquisar" runat="server" CssClass="btn btn-primary" Text="Pesquisar" OnClick="btPesquisar_Click" />
</div>
</div>
</asp:Panel>
</div>
<ajaxToolkit:CollapsiblePanelExtender ID="cpExtFiltros" runat="server" TargetControlID="pnlFiltrosContent" CollapseControlID="pnlFiltrosHeader" ExpandControlID="pnlFiltrosHeader"
Collapsed="false" TextLabelID="lblTextFiltros" CollapsedText="Clique para exibir..." ExpandedText="Clique para esconder..."
CollapsedSize="0"></ajaxToolkit:CollapsiblePanelExtender>
Как проверить, свернут ли Ajax Control Toolkit CollapsiblePanelExtender с помощью JQuery?