Above is the default view of this script
Click the blue 'Install' button on OpenUserJS and follow the on-screen instructions
It will add a button below each episode that you have not watched, once clicked it will mark the episode as watched like so (compare Saturday's episodes)
Note: The bar + eye symbol will not appear for episodes that have not aired yet (with the exception of the current day, where time hasn't been taken into account yet)
It is possible to change the colours of the eye symbol, background colour and hover colour as well as the height and whether or not it will show for 'most popular' or not (due to there being many episodes listed), however this has to be done by editing the script; all instructions are given in the code, only the values need changing and the script will take care of the rest.