javascript - Why "Prevent this page from creating additional dialogs" appears in the alert box?

Question

In my Rails 3 application I do:

render :js => "alert("Error!\nEmpty message sent.");" if ...

Sometimes, below this error message (in the same alert box) I see: "Prevent this page from creating additional dialogs" and a checkbox.

What does this mean ?

Is that possible not to display this additional text and checkbox ?

I use Firefox 4.

Answer 1

It's a browser feature to stop websites that show annoying alert boxes over and over again.

As a web developer, you can't disable it.