TradersVE
I ask you how you cannot test javascript with phpbrowser and it is part of an application, there is application code that works with the web server.
99% cases you just don't ever need to test frontend part, how js behaves, just because all the important stuff is on the backend.
Test your backend with functional test suite for app features and you are done.
Sometimes you have some critical parts on js side, well, write few acceptance tests... You do not need to go all pages and actions with acceptance.
In even more rare cases, you have this heavy frontend widgets and rely much business on it, for that cases you have to test it thoroughly by acceptance tests.
Or if you have modern app with API like React, Vue, Angular or similar, just make a complete js test suite to test without real backend. Test backend (API) and frontend separately. Splitting like that helps in most complex frontend-heavy apps.
With all that, there is no need to use acceptance to tell that "page X" works. This can be done in functional test suite. Without any real server, without any real js.