hi,
could you please tell me more about the game and its scenario? perhaps some screenshots of the existing game in vb6 to get idea about it.
about the tools: I've used Unity3D (free edition with unity splash screen). unity3D can export the game to web browser that has the plugin of unity web player installed.
however, I've practiced some html5 canvas programming, and I think I can learn either phaser or pixi if required. I need some time since I've have parallel jobs.
thanks