Add JavaScript tests.

Run "npm install", then "npm test".

package.json

@@ -0,0 +1,11 @@
+{
+  "name": "xxx",
+  "private": true,
+  "description": "Tests for the JavaScript of xxx.org.za",
+  "scripts": {
+    "test": "node --test \"tests/js/*.test.js\""
+  },
+  "devDependencies": {
+    "jsdom": "^29.1.1"
+  }
+}