iTest only supports the built in internal browser (mozilla) and Internet Explorer 7. So, I am not sure why you would want to check the browser type.
You can get all the alert messages in iTest by running the "listPrompts" action.
So your test case steps would look like this:
eval var browser = navigator.appName;
eval var version = navigator.appVersion;
The response of listPrompts will have the values you are looking for.
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