A comprehensive audio player that attempts to recreate the cart experience
Actually, here is a better one. My original link did not include DS themes: https://downloads.khinsider.com/game-soundtracks/album/advance-wars-dual-strike-extended-themes-ds-gamerip-2005. There are 7 choices when searching the game. I think this link is the best one. Songs are much longer.
Found a site with more complete music: https://downloads.khinsider.com/game-soundtracks/album/advance-wars-1-2-original-gba-audio
Unsure if you are the owner of the macroland site the current music is from. It would be much better to use what I found above. The above loops much much better.
If you do not plan on changing the music hosting files, at minimum it would be best to change
"let volume = 0.5;"
to be
"let volume = 0.2;"