How to Detect Browser Tab Close Event in Javascript

In this tutorial, you will learn how to detect the browser tab close event in JavaScript. This can be useful if you need to perform certain actions before the user closes the tab, such as saving their progress or displaying a confirmation message.

There are a few different ways to detect the tab close event in JavaScript, but one of the most reliable methods is to use the beforeunload event. This event is fired just before the page is unloaded, which includes when the user closes the tab or navigates away from the page.

To use the beforeunload event, you can add an event listener to the window object like so:

window.addEventListener('beforeunload', function(event) {
  // Your code here

Inside the event listener function, you can perform any actions you need to before the page is unloaded. Note that any alert() or confirm() dialogs that you display will also be shown to the user when they close the tab, so be careful not to disrupt their workflow.

Here is an example of how you might use the beforeunload event to display a confirmation message to the user before they close the tab:

window.addEventListener('beforeunload', function(event) {
  event.returnValue = '';
  return 'Are you sure you want to leave this page?';

In this example, we are using the preventDefault() method to prevent the default behavior of the beforeunload event, which is to unload the page immediately. Then, we are setting the returnValue property of the event to an empty string, which is necessary to make the confirmation dialog appear. Finally, we are returning a string that will be displayed in the confirmation dialog. When the user clicks OK, the tab will be closed, and when they click Cancel, the page will remain open.

By using the beforeunload event in JavaScript, you can detect when the user is about to close the browser tab and perform any necessary actions before they do so.