Confirm JS cannot open third webpage in Customwebview

Please, i am finding it difficult to load the third webpage in custom webview.
The error apper from customwebview.OnJSAlert.
here is the error received

The method ConfirmJs takes a boolean, not an integer.

Please can you show me example of Boolean expression

True and False are the only two Boolean values.

(since App Inventor is made with Java)

Thank you I appreciate.
But the third webpage I want to load from custom webview is not loading.
Using the block I showed up, can you help me with likely solutions.