How can I use CKEditor 4.0 in jsfiddle or similiar JavaScript online editor?

Why can't you upload it to your server and link it?

I tried first http://www.jsdelivr.com/ and failed:

config.js and contents.css are not there. If you put them on your local and point CDN for ckeditor.js it doesn't work because CKEditor looks for those files within a predefined structure which is supposed to be under jsdeliver CDN but they are not there.

If you define CKEDITOR_BASEPATH to your local before ckeditor.js loads, you have to put any other CKEditor subfolder in your local because from now on CKEditor looks your local and then it doesn't make sense to use a CDN.

However this one works: http://cdnjs.com/

CDNJS has all default files and is configured for full editor, but you can define a custom configuration just after first load as defined here:

http://docs.ckeditor.com/#!/guide/dev_configuration

Note: You have to define full path of your custom config file as seen below:

<script type="text/javascript">
CKEDITOR.replace( 'editor1',
{customConfig: '//www.yourdomain.com/yourfolder/config.js'});
</script>

I've put this code just before body end tag of html file.