storage.js

function getDatabase() {
     return LocalStorage.openDatabaseSync("HelioPi", "0.1", "SettingsDatabase", 100);
}

function set(setting, value) {
   var db = getDatabase();
   var res = "";
   db.transaction(function(tx) {
        tx.executeSql('CREATE TABLE IF NOT EXISTS settings(setting TEXT UNIQUE, value TEXT)');
        var rs = tx.executeSql('INSERT OR REPLACE INTO settings VALUES (?,?);', [setting,value]);
              if (rs.rowsAffected > 0) {
                res = "OK";
              } else {
                res = "Error";
              }
        }
  );
  return res;
}

function get(setting, default_value) {
   var db = getDatabase();
   var res="";
   try {
       db.transaction(function(tx) {
         var rs = tx.executeSql('SELECT value FROM settings WHERE setting=?;', [setting]);
         if (rs.rows.length > 0) {
              res = rs.rows.item(0).value;
         } else {
             res = default_value;
         }
      })
   } catch (err) {
       //console.log("Database " + err);
       res = default_value;
   };
  return res
}