Merge branch '0906online'

src/router/router-guards.ts

@@ -31,7 +31,7 @@ export function createRouterGuards(router: Router) {
     if (to.path === '/attend-class') {
       let title = to.meta.title;
       if (to.query.type === 'preview') {
-        title = '预览';
+        title = '预览课件';
       }
       document.title = title ? title : ('音乐数字课堂' as string);
     } else {