Uploaded April 2026 | Updated September 2026, 1 week ago
If the application shows the "Leave page" popup using the "e.preventDefault()" method call in the "beforeunload" event handler, we can confirm it in the Cypress tests using a stub on the "BeforeUnloadEvent.prototype.preventDefault". This video shows the solution, for more read the blog post "window.onbeforeunload and Cypress" at glebbahmutov.com/blog/onbeforeunload
If the application shows the "Leave page" popup using the "e.preventDefault()" method call in the "beforeunload" event handler, we can confirm it in the Cypress tests using a stub on the "BeforeUnloadEvent.prototype.preventDefault". This video shows the solution, for more read the blog post "window.onbeforeunload and Cypress" at glebbahmutov.com/blog/onbeforeunload
