How to use web browser download api?

Question

In this article downloads on MDN, it says we can use downloads api to donwload a file, but code in the example of that article

var downloading = browser.downloads.download({
  url : downloadUrl,
  filename : 'my-image-again.png',
  conflictAction : 'uniquify'
}); 

downloading.then(onStartedDownload, onFailed);

will lead to Uncaught ReferenceError: browser is not defined. I ran this code in chrome console pannel. Did I miss something?

Answer 1

Look at the section of the MDN documentation that page appears in. The feature is only available to browser extensions, not to regular webpages (which is the context the Console runs in if you open it against a regular page).