Could you apply what you learned to improve this qb js interpreter? http://stevehanov.ca/blog/index.php?id=92 Fairly useless but would be a nice nostalgia trip to be able to run some of the 90s qbasic code that's still lying around in unswept corners of the internet :)
If the point is running old QBasic code in a browser, it's probably better to compile DosBox to HTML5 and run the original QBasic interpreter in that, as is done on archive.org: https://archive.org/search.php?query=subject%3A%22qbasic%22
