C1Calendar client side has a very rich client-side object model since its identical to the object model in the server-side control.
When a C1Calendar control is rendered, an instance of the client side calendar will be created automatically. This means that you can enjoy the convenience of accessing any property and method of the C1Calendar control without having to postback to the server.
For example, suppose a C1Calendar control with name C1Calendar1 is hosted on Web page, when the page is rendered, a corresponding client calendar object with the name C1Calendar1_Client will be created.
By using C1Calendar's client-side code, you can implement many features to your Web page without the need to send information to the Web server which takes time. Thus, using client-side code can increase the efficiency of your Web site.