fix firefox support (thanks @qwertychomp)

index.html

@@ -15,7 +15,8 @@
     <script type="module" src="js/ga4.js"></script>
     <script type="module" src="js/main.js"></script>
     <script type="module" src="js/popup.js"></script>
-    
+    <script src="https://cdn.jsdelivr.net/npm/bowser"></script>
+
     <meta property="og:title" content="Eaglercraft Client Collections" />
 <meta property="og:type" content="website" />
 <meta property="og:url" content="https://www.eaglercraft.win" />

js/isValidTag.js

@@ -1,8 +1,30 @@
 import htmlTags from '../json/html-tags.json' with { type: 'json' };
 import htmlVoidTags from '../json/html-tags-void.json' with { type: 'json' };
 
-export const unifiedTagCollection = [...htmlTags, ...htmlVoidTags];
+const browser = bowser.getParser(window.navigator.userAgent).getBrowser();
+
+export let unifiedTagCollection = [];
+
+if (browser === "Chrome") {
+    unifiedTagCollection = [...htmlTags, ...htmlVoidTags];
+} else if (browser === "Firefox") {
+    const htmlTags = await fetchMultipleJsonUrls([
+        `${window.location.origin}/json/html-tags.json`,
+        `${window.location.origin}/json/html-tags-void.json`
+    ]);
+
+    unifiedTagCollection = [...htmlTags];
+} else {
+    unifiedTagCollection = [...htmlTags, ...htmlVoidTags];
+}
 
 export default function isValidTag(tag) {
     return unifiedTagCollection.includes(tag);
+}
+
+/** @returns {Promise<string[]>} */
+async function fetchMultipleJsonUrls(urls) {
+    const responses = await Promise.all(urls.map(url => fetch(url)));
+    const jsonArrays = await Promise.all(responses.map(response => response.json()));
+    return jsonArrays.flat();
 }