Problem with Document.execCommand("copy")

Question

I am having a problem when copying values. I use Clipboard API but know Clipboard API only works with secure context (HTTPS), in my Beta it's only HTTP so Clipboard API doesn't work. So is there a way to use document.execCommand("copy") in this case? I can simulate my code that is having problems as follows:

let path = 'https://google.com' 
if(navigator.clipboard) {
  navigator.clipboard.writeText(path).then(function() {
    console.log("Success!")
  }, function() {
    console.log("Failed!")
  });
} else {
  // Using document.execCommand("copy")
  path.select();
  document.execCommand("copy");
}

And the problem I have is: Uncaught TypeError: path.select is not a function

Can someone help me with the use case of document.execCommand("copy")? Thanks very much