WEB: Launch executable from browser

Question

I was wondering how Roblox (website) manages to launch the roblox executable from their website: when you chose a game and press "play", my browser (chrome) asks me if I want to launch an application, and shows me the path. When I press "Launch App", it launches the roblox client which is on my computer.

Answer 1

For windows, you'd register an application to a uri scheme

Basically just set up a few registry keys and point them to your executable. The best place to set this up is in your installer.

These are the keys you would set:

HKEY_CLASSES_ROOT
   Roblox
      (Default) = "URL:Roblox Launcher"
      URL Protocol = ""
      DefaultIcon
         (Default) = "roblox.exe,1"
      shell
         open
            command
               (Default) = "C:\Program Files\Roblox\roblox.exe" "%1"

Then from your website you could link to roblox:Hello%20World, which would launch your application as if the user had entered "C:\Program Files\Roblox\roblox.exe" "roblox:Hello World" on the command line.