Sure! Here's a simple example of how you can implement a Super Smash Bros-themed game using JavaScript and HTML:
This implementation allows the user to choose between Sonic or Donkey Kong to fight Sans. Sonic deals 5 damage, while Donkey Kong deals 10 damage. After selecting a character, the player can choose a stage (Final Destination or Battlefield). The game then alerts the player about their selections and starts the fight against Sans. Once Sans' health reaches 0, a victory message is displayed.
Please note that this is a simplified example for demonstration purposes and can be further enhanced with additional features and graphics as desired.