right, thanks for the hint to use https. After upgrading my router I forgot to enable luci-ssl. I now enabled https again.
But how can I identify the correct URLs to enable/disable wifi? I couldn'f find anything about http methods to control wifi in the references you provided.
It seems that it used to be possible to disable wifi using "cgi-bin/luci/admin/network/wireless_shutdown/radio0.network1". Maybe the URL changed in a newer openwrt version?
Anybody?