Min files.
Check for non-existent player_id.
Min version.
To debug.
Null check.
Debuug.
Emptiness check.
Min.
Null check for player_id on server.
Debug.
Use nextElementSibling instead of nextSibling
Use previousElementSibling instead of previousSibling.
Set width of select box.
Easier markup.
Validation checks.