XMLHttpRequest Origin null is not allowed Access-Control-Allow-Origin for file:/// to file:/// (Serverless)

For instances where running a local webserver is not an option, you can allow Chrome access to file:// files via a browser switch. After some digging, I found this discussion, which mentions a browser switch in opening post. Run your Chrome instance with:

chrome.exe --allow-file-access-from-files

This may be acceptable for development environments, but little else. You certainly don't want this on all the time. This still appears to be an open issue (as of Jan 2011).

See also: Problems with jQuery getJSON using local files in Chrome

Essentially the only way to deal with this is to have a webserver running on localhost and to serve them from there.

It is insecure for a browser to allow an ajax request to access any file on your computer, therefore most browsers seem to treat "file://" requests as having no origin for the purpose of "Same Origin Policy"

Starting a webserver can be as trivial as cding into the directory the files are in and running:

python -m http.server

[Edit Thanks @alextercete, for pointing out that it has updated in Python3]

This solution will allow you to load a local script using jQuery.getScript(). This is a global setting but you can also set the crossDomain option on a per-request basis.

$.ajaxPrefilter( "json script", function( options ) {  options.crossDomain = true;});