You ask as developer or as end-user?
As an end-user, of course
Well, modern WebGl apps are targeted to OpenGL ES 3.0, which itself requires OpenGL 4.3 support. Only Haswell and newer generations have full support of current OpenGL versions.
About load on IGP, WebGL apps are usually a light-weight demos and casual games, because full-fledge game will be too large to fit into browser and likely will use a plugin with more capable rendering engine like Unity. But this will be changed with HTTP 2.0, because binary transfers will make possible game resources streaming and fast interactions.
What about this , http://potree.org/
This example can manage millions of points.
What can be the behaviour and effort of intel card?
Which can be the limits ? Which alerts could be recommended (if any) ?
Finally, where are the limits to say 'your card may be damaged' ?
Intel GPUs have same protections as discrete: if temperature or voltage become over limit, they will switch to lower performance levels or start throttling. In HD530 does not reach full clock speed, "Fuses Limit" you can see an example of GPU defense.
Thank you very much!