1. A method of processing user events on a plurality of threads, the method comprising: receiving a user event at a touchscreen of an electronic device curing display of a document by the touchscreen; dispatching the user event to a main thread of a web browser and to a secondary thread of the web browser, wherein the main thread of the web browser is configured to process user events and non-user events; after a predetermined period of time has elapsed following the start of processing of the user event by the main thread or dispatch of the user event to the main thread, processing the user event by the secondary thread, wherein the secondary thread is configured to process the user event using a default handling method; upon completing processing of the user event by the main thread, updating the display of the document according to the processing completed by the main thread; and notifying the second thread to terminate by the main thread, in response to the completion of the processing.