Well, I do know that it works for Shadowrun. It appears you're correct that it doesn't work for every game. I tried using it to get a Skyrim mod, and it didn't work. The page claims that it works for "any Steam game that supports public downloads", and the message I got for the Skyrim mod was "This file can't be publicly downloaded from the Steam Servers." I don't really know how the whole thing works or what exactly the difference is between public downloads and whatever Skyrim does. My guess would be that the downloader doesn't work for games that require Steam in order to launch, but that's just a guess.
I believe whether or not game mods are "publically downloadable" is set by the game's Steam workshop configuration (i.e. by the developers of the game), and is (I think) not necessarily related to whether the game requires the Steam client to launch.
I would recommend that if anyone finds games with such workshop restrictions, to take this up with the game's developers in the first instance and tell them to open up their damn workshop!
EDIT: Recently discovered a way to get ALL mods! However, it's slightly more work - even more so since the script requires editing before it will work.
1) Grab and install a script tool plugin for your browser, such as GreaseMonkey for firefox. Suggestions available from the GreasyFork main page: https://greasyfork.org/en
2) Download the Enhanced Steam Workshop Downloader, and install it (if you've installed one of the aforementioned script plugins, you should get auto-prompted to do this): https://greasyfork.org/en/scripts/29538-enhanced-steam-workshop-downloader
3) This is the annoying bit: It doesn't work as-is, at least not with the latest GreaseMonkey. So, as per this discussion topic (https://greasyfork.org/en/forum/discussion/33459/x
), Go to your GreaseMonkey (or whatever tool) tab on your browser, find the Steam Downloader Workshop script, select it, then select Edit Script. Then just replace all instances of "GM_xmlHttpRequest" with "GM.xmlHttpRequest" (without the quotes of course).
4) After that, whenever you navigate to a mod on the Steam Workshop, the script should install some extra buttons, including a download button. Press the download button, and the mod is yours! No need to subscribe, and works with "non-public" workshops!*
*That I've tested, which isn't many. Should also work on everything the SteamDownloader website works on (in theory). Also note I've only tested this with GreaseMonkey on Firefox - the script SHOULD be compatible with other similar scripting tools, but I have no idea if that's actually the case as this is the first time I've tried to use it.
The cool thing with this approach, is that once installed (and fixed to actually work), you don't need to go to a separate website to download the mod - it's just done seamlessly from within the Steam Workshop mod itself.
Thank you for your patiently guide,but may I ask why while clicking the button there is nothing show off but refresh the website again.