The Upload for ASP.NET Web Forms controls have a very rich client-side object model since most of their members are identical to the members in the server-side control.

When a C1Upload control is rendered, an instance of the client-side control will be created automatically. This means that you can enjoy the convenience of accessing properties and methods of the C1Upload controls without having to postback to the server.

Using client-side code, you can implement many features in your Web page without the need to send information to the Web server, which takes time. Thus, using the client-side object model can increase the efficiency of your Web site.