Why is the script not working. The color does not change and the header is not imported from another html file?

Question

css

Please help, I'm a front-end beginner.

Answer 1

The script is executed before the document is loaded. To fix this, you need to wrap the script in

window.onload = function() {
  //Содержимое
}

If you are asking a question related to code - it is better to upload the code to the sandbox ( codepen.io or jsfiddle.net )