If you call the JavaScript confirm() function more than once, Chrome will helpfully offer a checkbox saying "Prevent this page from creating additional dialogs."

This checkbox causes a surprising UX problem:

A developer seeing the checkbox will likely understand that it's a Chrome feature to stop misbehaving web pages from continuously stealing focus.

However, many users will interpret it to mean "Don't ask me again". For example, say a web app has a "remove" button that runs `confirm('Do you really want to remove this item?')`.

1. User clicks "remove" on item 1.
2. confirm() dialog pops up, user clicks "OK".
3. User clicks "remove" on item 2.
4. confirm() dialog pops up again, offering "Prevent this page from creating additional dialogs."
5. User thinks, "I'll check this box so it won't ask me for confirmation again as I remove more items" - checks box and clicks OK.
6. User clicks "remove" on item 3.
7. confirm() doesn't show a dialog and immediately returns false, so nothing happens.
8. User tries clicking "remove" again, but still nothing happens. The button has simply stopped working.
8. User is very confused and sends email to developer of web app, complaining that the "remove" button seems to stop working after a while.

As a developer of a web app, I have gotten many such reports from users when I started using the confirm() function. As a result, I'm having to render a modal dialog with HTML instead. Chrome's confusing UI is essentially making the confirm() function unusable.

This happens in current Chrome (v50 stable, v53 canary). Firefox is similarly affected, but IE and Safari are unaffected.

Safari solves the focus-stealing problem by allowing you to still close the tab or window while a confirm() dialog is showing. As a result, Safari can do without a "Prevent this page..." checkbox. I think Safari's behavior is better, and I'd like to suggest adopting it for Chrome.