Add offline Q&A

assets/javascripts/templates/pages/offline_tmpl.coffee

@@ -1,6 +1,32 @@
-app.templates.offlinePage = (docs) ->
-  """ <h1 class="_lined-heading">Offline</h1>
-      <table class="_docs">#{docs}</table> """
+app.templates.offlinePage = (docs) -> """
+  <h1 class="_lined-heading">Offline Documentation</h1>
+  <table class="_docs">#{docs}</table>
+  <h1 class="_lined-heading">Questions & Answers</h1>
+  <dl>
+    <dt>How does this work?
+    <dd>Each page is cached as a key-value pair in <a href="https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API">IndexedDB</a> (downloaded from a single JSON file).<br>
+        The app also uses <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Using_the_application_cache">AppCache</a> and <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_Storage_API">localStorage</a> to cache the assets and index files.
+    <dt>Can I close the tab/browser?
+    <dd>#{canICloseTheTab()}
+    <dt>What if I don't update a documentation?
+    <dd>You'll see outdated content and some pages will be missing or broken, since the rest of the app (including data for the search and sidebar) uses a different caching mechanism and is updated automatically.<br>
+        Documentation versioning is planned for the future but not yet supported, sorry.
+    <dt>I found a bug, where do I report it?
+    <dd>In the <a href="https://github.com/Thibaut/devdocs/issues">issue tracker</a>. Thanks!
+    <dt>How do I uninstall/reset the app?
+    <dd>Click <a href="javascript:app.reset()">here</a>.
+    <dt>Why aren't all documentations listed above?
+    <dd>You have to <a href="#" data-pick-docs>enable</a> them first.
+  </dl>
+"""
+
+canICloseTheTab = ->
+  if app.AppCache.isEnabled()
+    """ Yes! Even offline, you can open a new tab, go to <a href="http://devdocs.io">devdocs.io</a>, and everything will work as if you were online (provided you downloaded all the documentations you want to use beforehand).<br>
+        Note that loading any page other than <a href="http://devdocs.io">devdocs.io</a> directly won't work (due to limitations in AppCache). """
+  else
+    """ No. Because AppCache is unavailable in your browser (or has been disabled), loading <a href="http://devdocs.io">devdocs.io</a> offline won't work.<br>
+        The current tab will continue to work, though (provided you downloaded all the documentations you want to use beforehand). """
 
 app.templates.offlineDoc = (doc, status) ->
   html = """<tr data-slug="#{doc.slug}">"""