Many users will use browser tabs in any case, because they are used to do so.
So whatever you do, you should verify that browser tabs will work correctly and having the site open in multiple windows or tabs will not break the application.
Now, since you have to do most of the work for B in any case, are there any remaining reasons to do A also? That will ...
If you need some special/specific behaviors that can't be (easily) replicated using browser tab. i.e.
Code comparison, search in all tabs/files,... like in web IDEs.
Detach/Attach, show/hide, lock/unlock tabs/windows positions in image editor.
If you need to synchronize data between tabs. i.e.
When I click Save, I want to save the data in ...
Potentially, it is desirable to use browser tabs, as they are closer to the user browsing experience, BUT if you are building your own web app then you would be better to implement your own tab system within your app, because for your user, it would be easier to use and keep focused on.
Using browser tabs will disrupt your user's experience within your web ...
Overall my opinion is that using browser tabs would be the more familiar experience for the user and easier for them to work with. Absent compelling reasons to use in-app tabs, the overhead of implementing them and the potential confusion to the user seem like good reasons to avoid them.
Some thoughts on preferring browser tabs:
the user is already familiar ...
That depends on how tabs/pages are related in your application; but speaking of a more general scenario:
Are the tabs related amongst them i.e. different parts of the same information? Or are them different instances of the same page with different information?
In the former, tabs inside the app make sense, while in the latter navigator tabs (or "...
It's not a matter of better, it's what is the problem trying to be solved.
I don't have any real details about your use case, but you can see some logic applied across a range of domains.
A: Open in application tab
This allows for a feeling of continuity inside the application.
These tabs are usually located in subnavigation, so they provide specific ...