glTF and Javascript

Hi,
I'm not even sure this is the right place for this discussion, if it's not,
I apologize. What I'm curious about is glTF - this is the model format for
the web, right? Well, if a glTF model is displayed in the browser, is it
possible to *tamper with that model* in Javascript?, ie. do animation or
whatever? I went through the X3D docs on the web recently, and that
suggested you COULD do such a thing - and glTF is the successor to X3D,
right? So - is it possible? How, please?

Thanks