ReplaceCKEdit.js

var CKEDITORPluginExtras = false;

if (typeof(CKEDITOR) != 'undefined' ) {

    CKEDITOR.on('instanceReady',function(event, instance){
        if (CKEDITORPluginExtras) {
            return;
        }
        var config = event.editor.config;
        CKEDITOR.instances.body.destroy();
        // Do any manipulations you like on config here
        //
        //
        
        CKEDITOR.replace('body', config);
        CKEDITORPluginExtras = true;
    });

}