I have been requested to provide a tutorial on how to use the file upload feature of the TbRedactor widget, and even though I am no longer supporting the library due that the work belongs to Clevertech, I feel that I owe that to the Yii developers. So, here is the tutorial.
CHtml::ajaxLink(), CHtml::ajaxSubmitButton() and similar methods are great, but if they are located inside a portion of the page that is already loaded via ajax something bad will happen, something you may even not notice if you are not using tools like firebugs: the sent ajax requests will multiply themselves.
There are several methods and techniques that come handy in the case you need to call an external resource periodically or if you are waiting for a server push, but I present here an easy and straightforward one using HTML5's Server-Sent Events (SSE).
In Yii 1.x, there was a built in widget CStarRating based on the jquery star rating plugin. There exists no prebuilt solution in Yii2, however the same concepts can be extended using any jquery plugin.