The function can be used to automatically show dossier if the user has already logged in.
Otherwise, you can click or to log in.
This solution works on MicroStrategy 2021+, except Update 2. See another example for Update 2. This solution works for both SAML (loginMode=1048576) and OIDC (loginMode=4194304) authentications. Just need to change the loginMode parameter.
If you need this for MicroStrategy 2020, you need to add login-dialog.jsp to your library server under auth directory. You can find a copy in MicroStrategy 2021 Library Server.