The purpose is to warn users of context changes to minimize confusion on the user's part: changing the current window or popping up new windows can be very disorienting to users (in the case of a popup, no toolbar provides a "Previous" button to get back to the previous window). How to Display Spinner on the Screen till the data from the API loads using Angular 8 ? You can read more about it here. // This is likely caused by built-in popup blockers. CSS files, etc.). The onload event can also be used to deal with cookies (see "More Examples" below). I'm not sure what you mean, but I'd suggest looking through. Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. onload Event - W3Schools It represents the browser's window. javascript - window.onload vue - Why is window For example, if I want to have a pop-up, should I write (directly inside the