1. A method, comprising: in response to a user event received for a target element in a webpage, concurrently dispatching the user event for processing in a main thread and a secondary thread; processing the user event in the main thread using an event handler associated with said target element; processing the user event in the secondary thread using a default handling action defined for the webpage; and rendering the webpage for display by a first one of the main thread and the secondary thread upon said first one of the main thread and the secondary thread completing said processing of the user event.