What does preventDefault do and provide an example?

The preventDefault() method in JavaScript is used to cancel the default behavior of an event. For example, if a link has a click handler, calling event.preventDefault() will prevent the link from being followed.

Example:

const link = document.querySelector('a');
link.addEventListener('click', function(event) {
  event.preventDefault(); // Cancel the link navigation
  alert('Navigation canceled');
});

In this example, clicking the link will not navigate to the address, but instead will show a message. This is useful when you want to implement custom behavior instead of the default.