OAuth not working inside iframe

Question

I created a JSFiddle script that retrieves the OAuth access token through the Foursquare token response type. One or two days ago it worked fine. When “Login using the boxes” was clicked, the Foursquare login page appeared, and I was able to get access_token. Today I get the error "Failure to display the document because the display is prohibited by X-Frame-Options." I contacted JSFiddle to find out if they changed their X-Frame-Options headers, but I believe this is an iframed page that points to this header. What is the Foursquare OAuth policy inside iframes and has it changed recently?

Here is my violin

Answer 1

We updated the OAuth stream to not support implementation in iFrames. This is recommended by the OAuth 2 specification: http://tools.ietf.org/html/draft-ietf-oauth-v2-23#section-10.13