push.js: add file:// urls support

Fix for Android

Android was not working because the status is set to 200, not 0.

js/push.js

@@ -213,6 +213,8 @@
 
     options.container = options.container || options.transition ? document.querySelector('.content') : document.body;
 
+    var isFileProtocol = /^file:/.test(window.location.protocol);
+
     for (key in bars) {
       if (bars.hasOwnProperty(key)) {
         options[key] = options[key] || document.querySelector(bars[key]);
@@ -225,21 +227,25 @@
     }
 
     xhr = new XMLHttpRequest();
-    xhr.open('GET', options.url, true);
-    xhr.setRequestHeader('X-PUSH', 'true');
+    if (isFileProtocol) {
+      xhr.open('GET', options.url, false);
+    } else {
+      xhr.open('GET', options.url, true);
+      xhr.setRequestHeader('X-PUSH', 'true');
 
-    xhr.onreadystatechange = function () {
-      if (options._timeout) {
-        clearTimeout(options._timeout);
-      }
-      if (xhr.readyState === 4) {
-        if (xhr.status === 200) {
-          success(xhr, options);
-        } else {
-          failure(options.url);
+      xhr.onreadystatechange = function () {
+        if (options._timeout) {
+          clearTimeout(options._timeout);
         }
-      }
-    };
+        if (xhr.readyState === 4) {
+          if (xhr.status === 200) {
+            success(xhr, options);
+          } else {
+            failure(options.url);
+          }
+        }
+      };
+    }
 
     if (!PUSH.id) {
       cacheReplace({
@@ -259,6 +265,14 @@
 
     xhr.send();
 
+    if (isFileProtocol) {
+      if (xhr.status === 0 || xhr.status === 200) {
+        success(xhr, options);
+      } else {
+        failure(options.url);
+      }
+    }
+
     if (xhr.readyState && !options.ignorePush) {
       cachePush();
     }