Is the login form’s functionality actually that different from the registration form? They essentially need the same data to be filled in, they have similar purposes (the first creates an account, the second checks if a matching account exists). In fact many websites combine these forms, by putting them next to each other, on the same page. They just don’t use the same <form> tag.

I’m strongly against generated passwords: Most users never change them so they keep going back to check “that email” in order to log in (in case they didn’t store it in the browser). Also, it’s unrealistic and pointless to expect a registration form to be easier/faster to fill in than a standard login form, since the login form will probably be filled in a lot more frequently than the registration form.

I agree on your statement about website forms being the hardest website element to get right.

I also agree that my idea definitely needs refinment. That’s why I posted it in the first place.

As for pressing the enter key, that’s a very good point and I hate to admit that it’s something I missed when pointing out the drawbacks of the “one button for each function” approach. I guess if the user hits the Enter key, it should treat it as a login and if there’s no matching account and the username is free, provide the option to register.

I can appreciate the need to simplify; but why does that necessarily mean “to combine”? I feel, by combining two forms, both with very different functionality, you’re going to end up confusing quite a few users. I’m all for simplified registration forms; heck, I would go even further and just have an email field (we can send them a generated password), but I honestly don’t think the benefits of your solution outweigh the potential costs (as it currently stands).

I think forms are one of the hardest website elements to get right. It’s a constant compromise between convention, usability, simplicity and design. I don’t believe it’s been perfected yet… We need to keep on pushing for new approaches and ideas.

With a bit of refinement your idea is definitely worth trying… I like Paul’s idea of having two buttons also. (But be careful, many users don’t press a button; they press enter)

The “one button for each function” is an idea I also thought, but we should be careful in making the login button to stand out more than the register button (to avoid having users accidentally clicking “register”, and to make the register button to look like a button (and not a link), so that they understand that it’s sufficient to click it in order to register (if it looks like a link, they’ll probably assume that it will take them to an ordinary registration form).

If it changes to “login”, you could also put “Don’t have an account yet? Then we’re sorry, someone has already taken this username.”

By asking if you don’t have an account yet, you make it clear that the message isn’t intended for the existing user.

Another option would be to have two different buttons. One that says “login” and one that says “register”. That way you do the “username already taken” message once they click “Register”, but tell them “invalid password” if they click “login”