You're not going to be able to do this in javascript and HTML.
You will need extensive knowledge of Java, C# or C/C++ to create a webplayer for 3DGS. Remember that, because it is the SHIZ, anyone else would long have done that if it was so simple with javascript .

Even when somebody would succesfully make a webplayer, it would most likely require you to write 3DGS games in C#. You simply can't deploy .exe files on the internet easily like that, as it would cause a huge security issue. You'd need to provide a player that guarantees 3DGS games can not acces any files on the user's PC but those in the execution folder. The webplayer must provide access to DirectX and all other needed security-prone files. Well, that's one way to do it.

There is one solution offered in the past, I think it's still up but I don't have the link for it. It's written in Java but you need to pay for it. I guess that's no option for you?