diff --git a/src/lib/strings.js b/src/lib/strings.js
index a9cb973..1d9bc95 100644
--- a/src/lib/strings.js
+++ b/src/lib/strings.js
@@ -1,3 +1,5 @@
+const DEFAULT_LANG = 'en'
+
 export const strings = {
   en: {
     APP_TITLE: 'HTTP Cats',
@@ -7,7 +9,7 @@ export const strings = {
     USAGE_NOTE_TEXT: 'If you need an extension at the end of the URL just add',
     LANGUAGE_LINK_TEXT: 'Versió Català',
     DEVELOPED_BY: 'Developed by',
-    IMAGES_BY: 'Images by'
+    IMAGES_BY: 'Images by',
   },
 
   cat: {
@@ -19,12 +21,19 @@ export const strings = {
       'Si necessiteu una extensió al final de l’URL només heu d’afegir',
     LANGUAGE_LINK_TEXT: 'Versió Català',
     DEVELOPED_BY: 'Desenvolupat per',
-    IMAGES_BY: 'Imatges de'
-  }
+    IMAGES_BY: 'Imatges de',
+  },
 }
 
-const getString = label => {
-  const lang = window.location.search.indexOf('lang=cat') !== -1 ? 'cat' : 'en'
+const getString = (label) => {
+  const urlParams = new URLSearchParams(window.location.search)
+  const langParam = urlParams.get('lang')
+  const isKnownLang = langParam in strings
+  const lang = isKnownLang ? langParam : DEFAULT_LANG
+
+  if (isKnownLang && document.documentElement.getAttribute('lang') !== lang) {
+    document.documentElement.setAttribute('lang', lang)
+  }
 
   return strings[lang][label]
 }