Origin null is not allowed by Access-Control-Allow-Origin
by kiawin
If you are testing a simple ajax and found an error from Google Chrome’s element inspector,
XMLHttpRequest cannot load file:///. Origin null is not allowed by Access-Control-Allow-Origin.
High chances you are running the files directly from your computer (file://). Throw them in your localhost web server and it will work automagically.
My own dumb discovery :)