Can I have a touch input received as a general input?

I’m trying to add a touch input to an online game that I’m running on my website (joysticks and buttons) but I can’t seem to find anyway to have a general input. The game that I’m using is under license, in which the source code itself cannot be modified, so I can’t just replace the original source inputs.

I don’t have any code to post because ive tried a lot of solutions, none of which work.