What does the popstate event signify in the context of history manipulation?

The popstate event signifies a change in the active history entry. In the context of the History API, this event is triggered whenever the active history entry changes, which occurs when the user navigates back or forward between history entries using the browser's back and forward buttons. When a popstate event is fired, the associated state object can be accessed, allowing developers to retrieve the state information related to the current history entry.

This is useful for single-page applications (SPAs) where the content can change dynamically without causing a full page reload. By listening for the popstate event, developers can effectively manage the application state and update the displayed content according to the active history entry, enhancing the user experience while maintaining a logical navigation flow.