How browser's identify login forms?

Question

I'm trying to find out: how browsers identify login forms in different sites?

Doesn't matter if I'm acessing my GMail account or some personal project, IE/Firefox always knows that that page contains login info.

Do they conclude that simply searching for input types = password or there is some cookie information involved?

Thank you in advance.

Filipe

Answer 1

No only do they look for type=password they will also look for common input names for usernames and passwords.

For example most browsers will detect the following field names as login information.

<input name="login" type=text>
<input name="user" type=text>
<input name="username" type=text>
<input name="passwd" type="password">
<input name="pass" type="password">
<input name="password" type="password">

Answer 2

They look for input type=password.