HTML5 localStorage as a fallback for HTML5 WebSQL

public/javascripts/backbone/sync.js

@@ -15,9 +15,19 @@
  * Synchronization works both ways (supports multiple clients)
  **/
 
-// Which DB do you want to use today?
-persistence.store.websql.config(persistence, "webapp", 'database', 5 * 1024 * 1024);
-// persistence.store.memory.config(persistence, 'database', 5 * 1024 * 1024, '1.0');
+var supports_webdatabase = !!window.openDatabase
+var using_localstorage = !supports_webdatabase
+
+if (supports_webdatabase) {
+    // Empty methods which would be implemented by persistence.store.memory
+    persistence.loadFromLocalStorage = function(callback) { callback(); };
+    persistence.saveToLocalStorage = function(callback) { callback(); };
+    // Use WebSQL
+    persistence.store.websql.config(persistence, "webapp", 'database', 5 * 1024 * 1024);
+}
+else { // Use localStorage
+    persistence.store.memory.config(persistence, 'database', 5 * 1024 * 1024, '1.0');
+}
 
 /* */   // APPLICATION SPECIFIC CODE
 /* */
@@ -59,14 +69,14 @@ persistence.debug = true;
 var session = persistence;
 
 persistence.schemaSync(function(tx) { // First sync
-    // persistence.loadFromLocalStorage(function() { // if using localStorage
+    persistence.loadFromLocalStorage(function() { // if using localStorage
         ItemEntity.syncAll(persistence, server_sync_uri,
             persistence.sync.preferRemoteConflictHandler, function() {
                 console.log('First sync!');
         }, function() {
             console.log('Error syncing to server!');
         });
-    // });
+    });
 });
 
 
@@ -96,27 +106,29 @@ function sync(callback, item) {
 
 // Load elements from localStorage (if used) and sync with server (if dontSync == false)
 function load(callback, dontSync) {
-    // persistence.loadFromLocalStorage(function() { // if using localStorage
-        // console.log("All data loaded from localStorage!");
+    persistence.loadFromLocalStorage(function() { // if using localStorage
+        if (using_localstorage)
+            console.log("All data loaded from localStorage!");
         if (window.navigator.onLine && !dontSync) {
             sync(callback); // Sync to server
         } else {
             callback();
         }
-    // });
+    });
 }
 
 // Save elements to localStorage (if used) and sync with server (if dontSync == false)
 function save(callback, item, dontSync) {
-    // persistence.saveToLocalStorage(function() { // if using localStorage
-        // console.log("All data saved to localStorage!");
+    persistence.saveToLocalStorage(function() { // if using localStorage
+        if (using_localstorage)
+            console.log("All data saved to localStorage!");
         if (window.navigator.onLine && !dontSync) {
             sync(callback, item); // Sync to server
         } else {
             persistence.flush(); // Flush the new changes
             callback();
         }
-    // });
+    });
 }
 
 function readOne(model, success) {