1. In the Capabilities callback set these flags

caps["safariAllowPopups"] = true;
caps["autoAcceptAlerts"] = true;

First flag enables the prompt. The second - auto accepts it.  The downside of this approach is that all alerts will be auto accepted.

2.  Use this function whenever you need to accept an alert

function AcceptAlert()

Example in RVL

3. If you want to check the Alert text then use Navigator.DoCheckAlert. It will accept the alert if it's text matches the specified string.


JavaScript version

Navigator.DoCheckAlert("This site is attempting to open a pop-up window");

Note: Appium may be slow dismissing alerts but it works.