feat: finish bilingual session auth learning lab

web/assets/struts-lab.js

@@ -0,0 +1,92 @@
+(function () {
+    const LANGUAGE_KEY = "struts_lab_language";
+
+    function getLanguage() {
+        return localStorage.getItem(LANGUAGE_KEY) === "en" ? "en" : "zh";
+    }
+
+    function setLanguage(language) {
+        const resolved = language === "en" ? "en" : "zh";
+        localStorage.setItem(LANGUAGE_KEY, resolved);
+        document.documentElement.lang = resolved === "zh" ? "zh-CN" : "en";
+        return resolved;
+    }
+
+    function applyText(values) {
+        Object.entries(values || {}).forEach(([id, value]) => {
+            const node = document.getElementById(id);
+            if (node) {
+                node.textContent = value;
+            }
+        });
+    }
+
+    function applyHtml(values) {
+        Object.entries(values || {}).forEach(([id, value]) => {
+            const node = document.getElementById(id);
+            if (node) {
+                node.innerHTML = value;
+            }
+        });
+    }
+
+    function applyPlaceholders(values) {
+        Object.entries(values || {}).forEach(([id, value]) => {
+            const node = document.getElementById(id);
+            if (node) {
+                node.setAttribute("placeholder", value);
+            }
+        });
+    }
+
+    function mount(config) {
+        const state = {
+            language: setLanguage(getLanguage())
+        };
+        const button = document.getElementById(config.buttonId || "languageBtn");
+
+        function messages() {
+            return config.messages[state.language] || config.messages.zh || {};
+        }
+
+        function render() {
+            const current = messages();
+            if (current.pageTitle) {
+                document.title = current.pageTitle;
+            }
+            applyText(current.text);
+            applyHtml(current.html);
+            applyPlaceholders(current.placeholders);
+            if (button) {
+                button.textContent = state.language === "zh" ? "EN" : "中文";
+            }
+            if (typeof config.render === "function") {
+                config.render({
+                    language: state.language,
+                    messages: current,
+                    setLanguage
+                });
+            }
+        }
+
+        if (button) {
+            button.addEventListener("click", function () {
+                state.language = setLanguage(state.language === "zh" ? "en" : "zh");
+                render();
+            });
+        }
+
+        render();
+        return {
+            getLanguage: function () {
+                return state.language;
+            }
+        };
+    }
+
+    window.strutsLab = {
+        mount: mount,
+        getLanguage: getLanguage,
+        setLanguage: setLanguage
+    };
+})();