I'm not sure how to make this work. I need a Steam API key but I'm confused about how to get one. Going from your link, Steam is asking me for my domain name...?

Running .16, and when I go to a group and enter a game ID, it returns the same number for who owns/wants. I've tried multiple games, and it always returns the who owns number regardless of which button I press. The group wishlist shows only 2 people have it on wishlist, but your script says 62 have it wishlisted (same as owns number).

what a great script!!!!!!!!!!!!!!!!!!!!

Hey Gaffi
I tried using the script on my WL today but for some reason it doesn't work. Doesn't load the game name, stays stuck on "checking" but nothing happens. I still manage to run it without issue on my groups. Just not working with the WL. Anything I should do to try and fix the issue? Reinstall maybe?

also, forgot to say this:

awesome work, Gaffibud

An improvement idea (if you still have time for it ^^ )

When checking groups it'd be best to exclude inactive users. They are faded out in the user listing.

Google Chrome 65.0.3325.181 (Official Build) (64-bit)
Tampermonkey v4.5
SteamGifts Library Checker 0.17 + 2 other scripts deactivated
Tried several Steam ids, same games that I successful checked last time I used it (Mar 19th) and same groups.
Game name appears but the output field is stuck at "Checking group users..." and nothing happens.
Reset cache: done (or at least I clicked, I don't know if it actually did it then), nothing changes.
Copy-paste API again: it changes a lot, don't know if it's good or bad but now it says after some seconds "There was an error loading data from Steam. This could be a server or API problem. Please try again. If you cannot resolve, please report the error. Thanks!"
Maybe this is just a temporary problem? In case it's not and you need the console output, feel free to add me on Steam because it's quite long.

All Steam-links were changed to https which broke the script. Changing following lines fixes it ^^

175

var searchString1 = 'href="https://steamcommunity.com/profiles/';

276

var link = 'https://steamcommunity.com/profiles/' + steamID + '/wishlist';

462

var link = "https://store.steampowered.com/api/appdetails?appids="+appID;

Additional bug-fix:
When using the script after searching for a user in a group page it uses a wrong url and won't work.

910

groupURL = window.location.href.slice(0,indexUsers) + '/users/search?page=';

-

I've also implemented the inactive users ignore feature ^^
add before lines:

1247

if( inactive > 0 )
    document.getElementById('SGLCdlg-output').value += "\r\n" + inactive + " inactive users ignored.";

1246

if( inactive > 0 )
    totalScanned -= inactive;

1017

if( rows[i].className != "table__row-inner-wrap is-faded")
    inactive+=1;
    totalScanned+=1;
else

30

var inactive = 0;

I put the whole script here for quick copy:
https://pastebin.com/rQgCAd2f

Line 13

// @match       http://store.steampowered.com/app/*

Maybe should be turned to:

// @match       https://store.steampowered.com/app/*

because it didnt work before in the steam store.
i think steam goes to https by default now.

/edit
Interesting. If i am logged in it goes to https if i am not it goes to http;
Can you check out the difference an make the script change it's behavior accordingly?
/edit

You can get to the script HERE

click it, allow it to run and then:

View attached image.

This is an excellent script.
However, I am having the problem that both the "Who Has" and "Who Wants" is coming up with the same values (results) which can not be correct. For instance, I enter 317620 (Space Hulk Ascension) and it comes up that both 66 of 89 have and 66 of 89 want the game. Obviously, if you add those two figures together it comes out to more than the number of users in the group. Not sure if it is a script bug, or something on my end causing it. And I have tried to utilize the Clear Cache to resolve, but it makes no difference. Any input would be appreciated. Same results situation occurs for every game I check (each game having different results from each other, but Have and Want are both the same for each one).