I think it's activex based and not supported on modern systems... I seem to remember seeing something about these sort of plugin based things while digging around in the Thermovision SDK, potentially with fsviewer, but I think there's an IP camera viewer available from their legacy download site that has a secondary installer for the components, but while it would install I believe it threw directX issues when trying to run on windows 10. I'd try using an XP VM and see if those browsers or the legacy software can work for it.