Web client does not work without internet access in some browsers

I am sharing here the bug https://github.com/maia-sdr/plutosdr-fw/issues/15 just for information. I understand that using a self-hosted IQEngine within the Maia SDR firmware and no internet access is a rather niche use case, and that solving this bug will not be a priority. The TLDR is that apparently there are browsers that refuse to initiate the XMLHttpRequests that the IQEngine client does whenever they determine that there is no internet access. This is the case for Firefox under Linux (but there is a setting in `about:config` to fix this) and both Firefox and Chrome in Android (so far I don't know if these can be fixed). Interestingly this only seems to affect XMLHttpRequets. Other accesses, including those done with the JS Fetch API, work fine.