So i got some problems with my Wikipedia Viewer.
Link: http://codepen.io/Chepalos/pen/vxYJpK?editors=1111
Every time i search something i get an error message: XMLHttpRequest cannot load https://www.mediawiki.org/w/api.php?&action=opensearch&format=json&search=n. Origin http://s.codepen.io is not allowed by Access-Control-Allow-Origin.
I already figured out that this has something to do with COREs. So my Questions are why i get this messages, how can i fix this and where can i learn more about that topic?