[Build] revert site to webpack config (#3747)

docs/site/utils/iframe-router.js

@@ -0,0 +1,36 @@
+/**
+ * 同步父窗口和 iframe 的 vue-router 状态
+ */
+
+import { setLang } from './lang';
+import { iframeReady, isMobile } from '.';
+
+export function initIframeRouter() {
+  window.syncPath = function () {
+    const router = window.vueRouter;
+    const isInIframe = window !== window.top;
+    const currentDir = router.history.current.path;
+    const pathParts = currentDir.split('/');
+    let lang = pathParts[0];
+    if (currentDir[0] === '/') {
+      lang = pathParts[1];
+    }
+
+    if (!isInIframe && !isMobile) {
+      const iframe = document.querySelector('iframe');
+      if (iframe) {
+        iframeReady(iframe, () => {
+          iframe.contentWindow.changePath(lang, currentDir);
+        });
+      }
+      setLang(lang);
+    } else if (isInIframe) {
+      window.top.changePath(lang, currentDir);
+    }
+  };
+
+  window.changePath = function (lang, path = '') {
+    setLang(lang);
+    window.vueRouter.replace(path);
+  };
+}