Pretty funny, before I created this, I could nowhere find anything like it. Now, I'm done I found something...
https://chrome.google.com/webstore/detail/steamchecker/eopegaefgepfdedhecfbclehhffiebpk

Though, my 2 scripts have an advantage. It can better detect owned games, as the steam api I am using gives better results. His script looks more visually appealing though. :P

I'll use yours ( ͡° ͜ʖ ͡°). Thank you

Question: Is there any possibility that a script would do the same in the Humble Store? At least for me it is a pita to surf the Humble Store because with most of their deals, I always have to tediously doublecheck if I already own the game. It would be such a relief to see games I already own on Steam in the Humble Store.
I know, i know, my own fault vor owning so many games. But one can ask for a little bit of luxury, can one not? :)

It not working for me without "Steam Store - Game Owned Checker" or maybe i do not know where you put links? (Found it)
Could you add option for open Steam store links in new tab?

so dumb of humble to not have those links on their own. definitely installed, thanks! ^^

Is this intended for the download/claim page? It's not working and I'm not sure if it should or not.