1. AJAX Accordion control
Rehab AlFallaj

2. Accordion control
The Accordion is a web control that allows you to provide multiple panes and display them one at a time. It is like having several CollapsiblePanels where only one can be expanded at a time. The Accordion is implemented as a web control that contains AccordionPane web controls. Each AccordionPane control has a template for its Header and its Content.

3. First:
Add a ToolkitScriptManager
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
</asp:ToolkitScriptManager>

4. Second:
Add Accordion from Ajax Control Toolkit
<asp:Accordion ID="Accordion1" runat="server">
</asp:Accordion>

5. Third:
Add panes tag
<pane>
</pane>

6. Fourth:
inside the panes insert AccordionPane as much as you want:
1 AccordionPane = 1 section
2 AccordionPane = 2 sections
3 AccordionPane = 3 sections

7. Fifth:
inside each AccordionPane add a Header & a Content tags

11. Tutorial:
Video: