# OnClientRequestStart

The **OnClientRequestStart** occurs when a request to the Web Service is about to be sent. The event is raised only when the Gantt is bound to a Web Service and is raised for every request sent to the service, including all CRUD operations on tasks, dependencies, resources and assignments.

The event handler receives two parameters:

1. The instance of the Gantt control firing the event.

2. An **eventArgs** parameter containing the following methods:

* **get_type** returns the type of the request.

* **get_context** returns a context object (implements IDictionary) that is passed to the Web Service method that handles the request.

* **set_cancel** lets you cancel the event and stop the request.

```ASP.NET
<telerik:RadGantt RenderMode="Lightweight" runat="server" id="RadGantt1" OnClientRequestStart="OnClientRequestStart">
</telerik:RadGantt>
```

```JavaScript
function OnClientRequestStart(sender, eventArgs) {
    args.set_cancel(true);
}
```

The event can be used to [send additional information to the Web Service](https://www.telerik.com/products/aspnet-ajax/documentation/controls/gantt/data-binding/client-side-binding/sending-additional-information-to-the-web-service).

## See Also

* [Client-Side Basics](https://www.telerik.com/products/aspnet-ajax/documentation/controls/gantt/client-side-programming/overview)

* [Client-Side Events](https://www.telerik.com/products/aspnet-ajax/documentation/controls/gantt/client-side-programming/events/overview)