diff --git a/src/js/app/index.js b/src/js/app/index.js
index ef6e6fac..67b07755 100644
--- a/src/js/app/index.js
+++ b/src/js/app/index.js
@@ -233,7 +233,14 @@ function changeLocaleFromHeaders(langString) {
     var languages = langString.split(',');
     var desiredLocale;
     for (var i = 0; i < languages.length; i++) {
-      var lang = languages[i].slice(0, 2);
+      var header = languages[i].split(';')[0];
+      // first check the full string raw
+      if (intl.headerLocaleMap[header]) {
+        desiredLocale = intl.headerLocaleMap[header];
+        break;
+      }
+
+      var lang = header.slice(0, 2);
       if (intl.langLocaleMap[lang]) {
         desiredLocale = intl.langLocaleMap[lang];
         break;
diff --git a/src/js/intl/index.js b/src/js/intl/index.js
index 2f299be7..721064a4 100644
--- a/src/js/intl/index.js
+++ b/src/js/intl/index.js
@@ -9,6 +9,11 @@ var getDefaultLocale = exports.getDefaultLocale = function() {
   return 'en_US';
 };
 
+var headerLocaleMap = exports.headerLocaleMap = {
+  'zh-CN': 'zh_CN',
+  'zh-TW': 'zh_TW',
+};
+
 // resolve the messy mapping between browser language
 // and our supported locales
 var langLocaleMap = exports.langLocaleMap = {