webgl_enabled
Returns: Boolean
This read-only variable will return whether WebGL is
enabled (true) or not (false) for your game. It
will only work for those games running through a browser (ie:
HTML5), and for all other platforms it will return true.
if webgl_enabled global.quality = 1 else global.quality = 0;
The above code checks the WebGL flag and then sets the global variable "quality" accordingly.