Insert language setting based on the player's account.

data/gacha_details.html

@@ -81,11 +81,11 @@
         </footer>
 
         <script>
-            fiveStarItems = {{FIVE_STARS}};
-            fourStarItems = {{FOUR_STARS}};
-            threeStarItems = {{THREE_STARS}};
+            var fiveStarItems = {{FIVE_STARS}};
+            var fourStarItems = {{FOUR_STARS}};
+            var threeStarItems = {{THREE_STARS}};
+            var lang = "{{LANGUAGE}}";
 
-            var lang = new window.URLSearchParams(window.location.search).get("lang");
             function getNameForId(itemId) {
                 if (mappings[lang] != null && mappings[lang][itemId] != null) {
                     return mappings[lang][itemId][0];

src/main/java/emu/grasscutter/server/dispatch/http/GachaDetailsHandler.java

@@ -52,6 +52,8 @@ public final class GachaDetailsHandler implements HttpContextHandler {
 		response = response.replace("{{AVAILABLE_FOUR_STARS}}", translate(player, "gacha.details.available_four_stars"));
 		response = response.replace("{{AVAILABLE_THREE_STARS}}", translate(player, "gacha.details.available_three_stars"));
 
+		response = response.replace("{{LANGUAGE}}", Utils.getLanguageCode(account.getLocale()));
+		
 		// Get the banner info for the banner we want.
 		int gachaType = Integer.parseInt(req.query("gachaType"));
 		GachaManager manager = Grasscutter.getGameServer().getGachaManager();