No 'Access-Control-Allow-Origin' header is present on the requested resource error

If you use Google Chrome browser you can hack with an extension.

You can find a Chrome extension that will modify CORS headers on the fly in your application. Obviously, this is Chrome only, but I like that it works with zero changes anywhere at all.

You can use it for debugging your app on a local machine (if everything works in production).

Notice: If URL becomes broken the extension name is Access-Control-Allow-Origin: *. I recommend you to disable this extension when you not working on your stuff, because, for example, youtube does not work with this extension.


I believe this might likely be that Chrome does not support localhost to go through the Access-Control-Allow-Origin -- see Chrome issue

To have Chrome send Access-Control-Allow-Origin in the header, just alias your localhost in your /etc/hosts file to some other domain, like:

127.0.0.1   localhost yourdomain.com

Then if you'd access your script using yourdomain.com instead of localhost, the call should succeed.


Try this - set Ajax call by setting up the header as follows:

var uri = "http://localhost:50869/odata/mydatafeeds"
$.ajax({
    url: uri,
    beforeSend: function (request) {
        request.setRequestHeader("Authorization", "Negotiate");
    },
    async: true,
    success: function (data) {
        alert(JSON.stringify(data));
    },
    error: function (xhr, textStatus, errorMessage) {
        alert(errorMessage);
    }                
});

Then run your code by opening Chrome with the following command line:

chrome.exe --user-data-dir="C:/Chrome dev session" --disable-web-security