You are right, I did not have a clear idea of what I wanted... The fact is that I had a .svg image as output of a little program and I found out that browsers can read svg; moreover I had just learned HTML and I wanted to "try it out" to see how it was like. So this idea to use firefox stuck in my mind and I could not think of anything else.

However, it was just a for-fun-program, so I do not care if it is not perfect. Now I think the best solution would be to run a web server, but, actually, it does not worth. Of course I care of my program, but I am satisfied with having to run it manually and open its output in firefox.

I will try not to fall anymore in the XY Problem.