Before writing a login application, the following points should be clarified. These apply regardless of the rendering engine you are going to use.
- Number of dialogs
- Localization (Is the login application localized? If yes, which languages are required?)
- Language determination (By what means do you determine the language?)
- Rough sketch of layout (Usually a fixed area surrounding an input area that varies from dialog to dialog.)
- Security (Is the page safe regarding injection attacks, such as cross-site scripting?)