Origin null is not allowed by Access-Control-Allow-Origin

Origin null is the local file system, so that suggests that you're loading the HTML page that does the load call via a file:/// URL (e.g., just double-clicking it in a local file browser or similar).

Most browsers apply the Same Origin Policy to local files by disallowing even loading files from the same directory as the document. (It used to be that Firefox allowed the same directory and subdirectories, but not any longer.

Basically, using ajax with local resources doesn't work.

If you're just testing something locally that you'll really be deploying to the web, rather than use local files, install a simple web server and test via http:// URLs instead. That gives you a much more accurate security picture. Your IDE may well have some kind of server built in (directly or via an extension) that lets you just hit "run" in the IDE and have the server fired up and serving the file.

Just wanted to add that the "run a webserver" answer seems quite daunting, but if you have python on your system (installed by default at least on MacOS and any Linux distribution) it's as easy as:

python -m http.server  # with python3

or

python -m SimpleHTTPServer  # with python2

So if you have your html file myfile.html in a folder, say mydir, all you have to do is:

cd /path/to/mydir
python -m http.server  # or the python2 alternative above

Then point your browser to:

http://localhost:8000/myfile.html

And you are done! Works on all browsers, without disabling web security, allowing local files, or even restarting the browser with command line options.

Chrome and Safari has a restriction on using ajax with local resources. That's why it's throwing an error like

Origin null is not allowed by Access-Control-Allow-Origin.

Solution: Use firefox or upload your data to a temporary server. If you still want to use Chrome, start it with the below option;

--allow-file-access-from-files

More info how to add the above parameter to your Chrome: Right click the Chrome icon on your task bar, right click the Google Chrome on the pop-up window and click properties and add the above parameter inside the Target textbox under Shortcut tab. It will like as below;

C:\Users\XXX_USER\AppData\Local\Google\Chrome\Application\chrome.exe --allow-file-access-from-files

Hope this will help!