I got this error in Chrome while testing out a JQuery Mobile application. The problem was that JQuery Mobile app’s index.html was trying to open another local HTML file using “<a href="foo.html …". Opening local files is not allowed by default in Chrome (but works in Firefox and Safari). This is the kind of error you'd get in Chrome:
XMLHttpRequest cannot load file://.../foo.html. Origin null is not allowed by Access-Control-Allow-Origin.
To get rid of the error, you can enable local files in Chrome by adding "–allow-file-access-from-files" option (as explained here).
On Mac, I do this but running Chrome using the following command from terminal:
open /Applications/Google\ Chrome.app --args --allow-file-access-from-files