From fd634988af60712a1e7e8affba5e34e178f84164 Mon Sep 17 00:00:00 2001
From: zjcqoo <zjcqoo@gmail.com>
Date: Thu, 9 Sep 2021 16:25:40 +0800
Subject: [PATCH] add a fallback if js is disabled or sw is not supported

---
 README.md         | 25 +++++++++++++++++++------
 assets/js/tmpl.js | 13 +++++++++----
 2 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/README.md b/README.md
index 42a973f..2b746fe 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,25 @@ Source Files: https://github.com/fanhtml5/test-site
 
 ## FAQ
 
+Q: What if JavaScript is disabled?
+
+A: Unfortunately, the page can't be displayed. You can add a fallback in `404.html` such as:
+
+```html
+<noscript>
+  <meta http-equiv=Refresh content="0;url=FALLBACK_URL">
+</noscript>
+<script src=/x.js></script>
+```
+
+----
+
+Q: What if the browser doesn't support Service Worker?
+
+A: Same as above. The program will read the contents of `<noscript>` and render them.
+
+----
+
 Q: Is free CDN safe?
 
 A: Yes, the program will verify the data integrity.
@@ -59,12 +78,6 @@ A: Just overwrite `x.js`, the client polls this file every 2 minutes.
 
 ----
 
-Q: What if the browser doesn't support Service Worker?
-
-A: Unfortunately, the page can't be displayed. You can add a fallback in `404.html`.
-
-----
-
 Q: Will new features be added?
 
 A: This project is just an experiment, there is a new project named [freecdn](https://github.com/EtherDream/freecdn) which is much more powerful. (better docs will be released soon)
diff --git a/assets/js/tmpl.js b/assets/js/tmpl.js
index 6a1b70e..1eecb92 100644
--- a/assets/js/tmpl.js
+++ b/assets/js/tmpl.js
@@ -1,8 +1,12 @@
 function pageEnv() {
   var container = document.documentElement
 
-  function showErr(msg) {
-    container.innerHTML = msg
+  function fallback(html) {
+    var noscript = document.getElementsByTagName('noscript')
+    if (noscript.length > 0) {
+      html = noscript[0].innerHTML
+    }
+    container.innerHTML = html
   }
 
   function reload() {
@@ -16,11 +20,11 @@ function pageEnv() {
   if (jsUrl) {
     var sw = navigator.serviceWorker
     if (!sw) {
-      showErr('Error: Service Worker is not supported')
+      fallback('Service Worker is not supported')
       return
     }
     var swPending = sw.register(jsUrl).catch(function(err) {
-      showErr(err.message)
+      fallback(err.message)
     })
     rootPath = getRootPath(jsUrl)
   } else {
@@ -119,6 +123,7 @@ function pageEnv() {
   function loadNextUrl() {
     var url = URLS.shift()
     if (!url) {
+      fallback('failed to load resources')
       return
     }
     if (PRIVACY === 2) {