diff -r 000000000000 -r 6474c204b198 browser/base/content/test/general/browser_bug435325.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/base/content/test/general/browser_bug435325.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/* Ensure that clicking the button in the Offline mode neterror page makes the browser go online. See bug 435325. */
+
+let proxyPrefValue;
+
+function test() {
+  waitForExplicitFinish();
+
+  let tab = gBrowser.selectedTab = gBrowser.addTab();
+
+  // Go offline and disable the proxy and cache, then try to load the test URL.
+  Services.io.offline = true;
+
+  // Tests always connect to localhost, and per bug 87717, localhost is now
+  // reachable in offline mode.  To avoid this, disable any proxy.
+  proxyPrefValue = Services.prefs.getIntPref("network.proxy.type");
+  Services.prefs.setIntPref("network.proxy.type", 0);
+
+  Services.prefs.setBoolPref("browser.cache.disk.enable", false);
+  Services.prefs.setBoolPref("browser.cache.memory.enable", false);
+  content.location = "http://example.com/";
+
+  window.addEventListener("DOMContentLoaded", function load() {
+    if (content.location == "about:blank") {
+      info("got about:blank, which is expected once, so return");
+      return;
+    }
+    window.removeEventListener("DOMContentLoaded", load, false);
+
+    let observer = new MutationObserver(function (mutations) {
+      for (let mutation of mutations) {
+        if (mutation.attributeName == "hasBrowserHandlers") {
+          observer.disconnect();
+          checkPage();
+          return;
+        }
+      }
+    });
+    let docElt = tab.linkedBrowser.contentDocument.documentElement;
+    observer.observe(docElt, { attributes: true });
+  }, false);
+}
+
+function checkPage() {
+  ok(Services.io.offline, "Setting Services.io.offline to true.");
+  is(gBrowser.contentDocument.documentURI.substring(0,27),
+    "about:neterror?e=netOffline", "Loading the Offline mode neterror page.");
+
+  // Now press the "Try Again" button
+  ok(gBrowser.contentDocument.getElementById("errorTryAgain"),
+    "The error page has got a #errorTryAgain element");
+
+  // Re-enable the proxy so example.com is resolved to localhost, rather than
+  // the actual example.com.
+  Services.prefs.setIntPref("network.proxy.type", proxyPrefValue);
+
+  gBrowser.contentDocument.getElementById("errorTryAgain").click();
+
+  ok(!Services.io.offline, "After clicking the Try Again button, we're back " +
+                           "online.");
+
+  finish();
+}
+
+registerCleanupFunction(function() {
+  Services.prefs.setBoolPref("browser.cache.disk.enable", true);
+  Services.prefs.setBoolPref("browser.cache.memory.enable", true);
+  Services.io.offline = false;
+  gBrowser.removeCurrentTab();
+});