Thank you! I used RPG Maker MV, which has a web export option. I used some plugins to change the tile and screen sizes and adjust other stuff.
For RPG Maker 2000/2003 games, you might be able to use EasyRPG to make a browser port. If you're using the RM2k3 maniac patch, some of the added commands are supported by EasyRPG, but not all of them yet.