Take a look on the file:
https://bnetus-a.akamaihd.net/account/creation/static/js/flow/capture-arkose-{HASH}.js
There you can find the definition of onCompleted method - this code is executed when visitor successfully solves the captcha.
After a quick look into the code I suppose it does the following:
Places the token into the value of capture-arkose input
You can do the same like this:
JavaScript:
document.querySelector('#capture-arkose').value = 'TOKEN'
Enables 'Continue' button, so you can do the same:
JavaScript:
document.querySelector('#flow-form-submit-btn').disabled=false
Submits the form.
In my test i made both click on the button and called submit method on the form.
JavaScript:
document.querySelector('#capture-arkose').click()
document.querySelector('form').submit()
