Load xml file to browser's local storage

Hi, 

I was trying to directly load to the browser's local storage  a file saved and shared on dropbox, using an xmlrequest but I am getting the following error  'http://localhost' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Any help?

The use case is: user uploads to a common dropbox a file (using the API) later the user selects that file (which has a shared link associated) and  the file gets loaded to the local storage of the browser for further editing.