For Safari to autofill your username and password you must first activate this option:
Click on the "Edit Menu" > Preferences > AutoFill tab
- Check the box next to "User name and password"
- Close dialog box
- As from now on each time you log-in to a website, Safari will prompt you to save your password
- You can view all the saved logins here:
- "Edit Menu" > Preferences > AutoFill tab
- Click on the "Edit button" next to "Username and password"