gl.MULTISAMPLE is not defined in Canvas3D API?

[Stefan Monov76]

I wanted to call:

gl.enable(gl.MULTISAMPLE);

by analogy with the commonly used C code glEnable(GL_MULTISAMPLE);.

But gl.MULTISAMPLE has the value undefined. Is this because GL_MULTISAMPLE is part of a GL extension? Or why?

I thought perhaps I should use something like gl.MULTISAMPLE_ARB, but I tried printing Object.keys(gl) and none of the listed constants contained "MULTISAMPLE".