generating task information according to a selected first instant message in response to a first instruction for creating a task, displaying a task creation interface, and filling the task information into corresponding fields of the task creation interface for a user to edit;

creating the task according to values of respective fields in the task creation interface in response to a second instruction for confirming creation of the task, and hooking the task, as a shortcut, into a dialog box where the first instant message is located; and

detecting whether a duration between a current time and a preset time is shorter than or equal to a first time threshold, and if yes, pushing a third instant message into the dialog box so as to warn the user that there is a time limit for the task and the time limit is about to expire.