feat: header switch lang based on selection

assets/general.js

@@ -125,8 +125,11 @@ window.initDropdown = function() {
 
         $optionsList.off('click').on('click', 'li', function() {
             var newSrc = $(this).attr('data-src');
-            $selectedImg.attr('src', newSrc);
+            var langValue = $(this).attr('data-value');
-            $optionsList.removeClass('show');
+            var headerFile = (langValue === 'jp') ? "../header-jp.html" : "../header.html";
+            localStorage.setItem('selected_header', headerFile);
+            localStorage.setItem('selected_lang_src', newSrc);
+            window.location.reload();
         });
 
         $(document).off('click.dropdown').on('click.dropdown', function() {
@@ -144,12 +147,21 @@ window.loadHeader = function(callback) {
     }
 };
 
-fetch("../header.html")
+const targetHeader = localStorage.getItem('selected_header') || "../header.html";
+
+fetch(targetHeader)
     .then(res => res.text())
     .then(html => {
         const container = document.getElementById("header-container");
         if (container) {
             container.innerHTML = html;
+            
+            const savedLangSrc = localStorage.getItem('selected_lang_src');
+            const selectedImg = container.querySelector('#selected-img');
+            if (savedLangSrc && selectedImg) {
+                selectedImg.src = savedLangSrc;
+            }
+
             window.headerLoaded = true;
             window.loadHeaderCallbacks.forEach(cb => cb(container));
         }