Is there a way to simulate a click on an alert in JavaScript?

Question

I have a page with an iframe whose source page is in a separate domain. From time to time, the source page generates an alert. When it does so, it stops what it is doing until the user clicks OK to the alert.

What I would like to do is programmatically click OK on this alert so the source page can get back to being useful. Is this possible?

Answer 1

JavaScript is single-threaded, which means when you call a function, it blocks until it returns. When you call alert(), that passes control to the browser which decides how to handle it. It is not Javascript which is popping the UI dialog, it is the browser. alert() does not return until the browser receives the "OK" event and returns control. The javascript thread is halted until that happens.

So for at least two different reasons stated in the above paragraph, the answer is no :)

Answer 2

What happens if you override alert with a no-op in your code?

e.g.

<script>
// uncomment next line to swallow alerts
//  function alert(nope) { return; }
<script>
<script>
  $(document).ready(function() { alert("Hello, world!"); });
</script>

With the line commented out, alert appears. With line commented in, alert does not appear.