In JavaScript, which function is used to pause execution and wait for user input?

The function that is used to pause execution and wait for user input in JavaScript is prompt. When invoked, prompt displays a dialog box that prompts the user to enter some input. This dialog box halts the execution of the script until the user provides a response, either by entering text and clicking "OK" or by canceling the dialog. This behavior allows for user interaction within the script, making it possible to gather input dynamically at runtime.

In contrast, the other options function differently. The alert function is designed to display a message to the user but does not allow for any input; it only informs the user and requires them to acknowledge the message before the execution continues. The confirm function also presents a dialog to the user, but it only allows for a choice between "OK" and "Cancel." It returns a boolean indicating the user's choice but does not allow for text input. The input function is not a standard JavaScript function, making it an incorrect choice. Thus, prompt is the correct answer as it specifically facilitates user input while pausing script execution.