I was using webgl-experimental code do display a webgl-demo on a custom webpage on an XAMPP webserver. After that I tried some non-experimental code: https://webglfundamentals.org/webgl/webgl-skybox.html Changing the code to exactly the same like on the demo webpage (using CTRL-U to copy out the exact code) it didn't work.
Opening the demo in the same browser, it displays the running demo, but if I load it in my custom XAMPP webserver it won't load.
Why is it so? Is it also on the webserver dependent? How to install a debug console, that can also print webgl errors?