coding character sheets

Tool: Inline Variants

Paul Stefko
Aug 1, 2022
We take a look at a tool for displaying different content based on a page's URL search parameters.
📕 3 min.

If you have an adventure or supplement that you want to distribute for multiple game systems, you can always create different document for each set of rules. But that gets tedious fast, especially if you want people to be able to switch between them easily.

With a tiny amount of JavaScript, however, you can actually write a single HTML document and let the user choose which variant of the material they want to see when they load the page. Let's dig in.

As with all our tools, you can find this one at GitHub.


The code for this one is actually so short that I'm just going to put it right here:

const params = (new URL(document.location)).searchParams;

if (params.has("system")) loadVariant(params.get("system"));

function loadVariant(v) {
const variantList = document.querySelectorAll(`.${v}`);
const hiddenList = document.querySelectorAll(`*:where(.variant):not(.${v})`);
hiddenList.forEach(el => document.body.removeChild(el));

Walking through it, we first grab the search parameters of the loaded page and store them in params. This means anything after the normal URL of the page, starting with a question mark ?. Each parameter has a key and a value, joined by an equal sign =, and multiple parameters are separated by an ampersand &.

Our code only cares about the parameter system. If the URL has this parameter, we run the loadVarian() function with the value of system as the argument. This function finds any element on our page with the CSS class variant and another class equal to the value of system. Any other element with the variant class but without the class equal to system is deleted from the page.

Using the Tool

It's so simple to use this tool. Anywhere in your document that you want to have variant content, just wrap it in a <div> (or another appropriate element) with the variant class and another class called whatever you want to name the variant.

You can style these classes if you'd like. In our example, I styled variant with a border just to call it out, and each system got a ::before pseudo-element labeling which rules it uses.

To access a particular variant, all you have to do is put the search parameter at the end of the URL, in the form ?system=value. When you do this, the page will load with only the chosen content with the class value. (Without this parameter, all content will be in place. That's why I added the label pseudo-elements.)

In the example, loading the page with ?system=fate will display stats for an adult red dragon in my Fate-based game Crashing Beasts & Crumbling Halls. With ?system=pf2e, you get the stats for Pathfinder 2nd Edition.


There you have it: an incredibly simple way to serve one document to multiple audiences. This version is most useful if you are providing links to the document on a web server, and you control the search parameters. In the future, I plan to make an alternative to this tool that lets you toggle between different variants interactively.