Thank you very much for your advices. Unfortunately, this is only the tip of
the iceberg (hope this expression exists in english).
My experience with LibreJS is that half of the web breaks up.
Openstreetmap doesnt work (though one can use marble, a browser implemented
function would be nice); you can't check out with paypal; lots of sites for
searching appartments or cars etc. don't work.
You can't enter most adult sites (come on, someone has to say it).
I think it's really disastrous for the free software movement that the web
evolved this way.
But can we really hope to change the whole web?
And can this be done with a "non-free javascript-complain" button?
The problem with non-free bios seems a small one, compared to this.