How to change user role with external js?


it is very clear question as is also understood from. I just want to controle user moderatör role. how can i do that with this js?


There is no such option, there can be one moderator (the first to enter) or if configured on the server (prosody module) all are moderators.
And in general if you can control this from js, this means everybody can control this then there is no point of having it, this should be serverside decision if you want to be secure.