Most of the popular codes in code playground are of html, css, js. Why c++ or python code are not there?

Answer 1

A lot of people tend to start with something simpler before they get into tougher ones. I am not saying python is really tough but we know web is simpler.

Another reason is that, web application seems to be more popular because it can work anywhere provided you have a web browser on that device.

Answer 2

Because web codes are more interactive. And you can't do graphics with the other ones here.