A mechanism is disclosed for allowing an application to perform specified operations in response to occurrences of a specified event relative to a specified Smart Card-accessing device. A customized API is exposed to the application. The application invokes an "addEventListener" method of the API. The invocation of the method specifies, as parameters of the method, at least a Smart Card-accessing device, a type of event, and a function. The server computer executing the application detects the invocation of the "addEventListener" method. In response to detecting the invocation, the server determines the type of the event specified by the invocation, and starts a mechanism that executes the specified function each time that an event of the specified type occurs relative to the specified Smart Card-accessing device. Consequently, the application does not need to be programmed to poll the specified Smart Card-accessing device at specific times during the application's execution.