Sys.UI.DataView.isFetching Property
Gets a boolean value indicating whether the data is being retrieved.
Note
To get property values for client API properties, you must call the property accessor method that is named with the get_ prefix. For example, to get a value for a property such as cancel, you call the get_cancel method.
var a = MyDataView.get_isFetching();
Return Value
true if the data is currently be retrieved, otherwise false.