webgui: add warning when canvas method want to be executed
webgui: add warning when canvas method want to be executed

Now happens when JS canvas want toggle log states
karies/root,karies/root,olifre/root,olifre/root,olifre/root,zzxuanyuan/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,karies/root,karies/root,zzxuanyuan/root,karies/root,zzxuanyuan/root,zzxuanyuan/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,zzxuanyuan/root,olifre/root,zzxuanyuan/root,olifre/root,root-mirror/root,karies/root,zzxuanyuan/root,zzxuanyuan/root,zzxuanyuan/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,karies/root,karies/root,zzxuanyuan/root,olifre/root,zzxuanyuan/root,zzxuanyuan/root,root-mirror/root,root-mirror/root