Do you mean Chrome? You need at least version 87 of Chrome for BBC BASIC to work.
Can I remind you (and everybody) that one reason why the in-browser edition of BBC BASIC has only just become available is that the browser features necessary for its operation were only introduced recently (in the last few weeks in most cases). They would have been supported much earlier had it not been for the Spectre and Meltdown exploits, but disabling them was necessary as a protection.
Only now have ways been found to enable those features safely, which means you need the latest Browser versions to support them and to run BBC BASIC. If your hardware is so old that you cannot install Vivaldi it will probably never be able to run the in-browser edition of BBC BASIC (and remember that the in-browser edition is 3-4 times slower than the native edition, so it might be unusably slow anyway).