Expander for ASP.NET Web Forms allows you to show or hide embedded or external content within an expanding panel using various animation effects. C1Expander includes several unique features, including the following:

• Expand Directions
  C1Expander has the ability to expand in several different directions. The ExpandDirection property indicated in which direction the control expands and can be set to Top, Right, Bottom, and Left. See Expand Direction for more information.
• External Content
  You can show external content in the control using the ContentUrl property. This means that you can have the content of another Web page in your project or even the content of a Web site outside of your project appear in a C1Expander. For more information see Displaying External Content.
• Animation
  Expander includes built-in animation effects, such as linear or elastic easing, that can be set when the control is expanded or collapsed. Customize how animations are transitioned using the built-in animation transition option. You also have the ability to modify the length of the animation effects.
• Page Load
  You can choose whether or not the C1Expander control is initially expanded on page load by using the Expanded property. By default the Expanded property is set to True and the control is initially appears expanded. See Initial Expand State for more information.
• Theming
  With just a click of the SmartTag, change the expander's look by selecting one of the 6 premium themes (Arctic, Midnight, Aristo, Rocket, Cobalt, and Sterling). Optionally, use ThemeRoller from jQuery UI to create a customized theme!
• CSS Support
  Use a cascading style sheet (CSS) style to define custom skins. CSS support allows you to match the expander to your organization's standards.