Loading URL
The convar sv_loadingurl allows a server owner to define a webpage to show to players when joining the server.
Setting your server's loading URL
If you are setting the convar through the console then make sure to put quotes around the URL. Also a + should be added to the front. Your command should look something like this:
If you are placing this into your autoexec.cfg configuration file, be sure to remove the +, like so:
If you want, you may also use %s or %m in your URL (most likely in a GET variable) to pass the steam id, and map name respectively. For example:
These can be later retrieved with simple PHP code.
Custom loading pages
This section will not detail creating your page, and assumes you have already designed one.
Javascript functions
There are several Javascript functions which are called directly by Garry's Mod. To use these, simply create a function with that name in your page - it will be called when the event associated with it happens.
PHP GET parameters
%m and %s will be replaced with the server's current map and the player's 64-bit steam community ID, respectively. This means you can grab them using PHP's $_GET superglobal.
The map is a string, so you should have no trouble making use of that. However, the steam community ID is not the classic "shorthand" steam ID often seen in-game. A method of conversion (using PHP's bcmath & bcsub) is shown below.
Example
If you would like to use a local file as a loading screen, for example during gamemode creation as a default loading screen, you can use the asset:// prefix. The example uses the default loading screen, but any html file can be used.
Example
If you would like to use a simple image as a loading screen, but don't have a webhost, you can use the following code as your sv_loadingurl
value. Make sure to replace URL-GOES-HERE
with the link to the image you would like to use. This makes use of Data URIs for writing HTML for the URL.
Ready to use examples
gmod-lsm.com
A free, online and easy-to-use loading screen maker, without having to code anything or rent a web server. https://www.gmod-lsm.com
Load Seed
An application skeleton for building a loading screen. You can use it to quickly get started building your design. Make sure to read the readme before getting started. https://github.com/glua/load-seed
gmodload.com
A completely free loading screen creator, with no coding, no webserver, and no watermarks. https://gmodload.com/