title: Error making a request in IndexedDB
body: <p>I'm using IndexedDB and I created this function where I just want to add a new object.</p>
  
  <pre><code>var request = indexedDB.open("db", 1);
  request.onsuccess = function(event){
     request = event.target.result;
     var transaction = request.transaction(["cart"], "readwrite");
     var store = transaction.objectStore("cart");
     var obj = {
      w : w,
      x : x,
      y: y,
      z: z
     };
     var requestAdd = store.add(obj);
     requestAdd.onsuccess = function(w){
        console.log("great");         
     }
     request.close();
  }
  </code></pre>
  
  <p>Here is how I create my indexes and the objectStore</p>
  
  <pre><code>var storeCart = db.createObjectStore("cart", { autoIncrement : true });
          storeCart.createIndex("w", "w", {unique: false});
          storeCart.createIndex("x", "x", {unique: false});
          storeCart.createIndex("y", "y", {unique: false});
          storeCart.createIndex("z", "z", {unique: false});
  </code></pre>
  
  <p>But, for some reason, when I tried to access <code>cart</code> I get this error:</p>
  
  <pre><code>NotFoundError: The operation failed because the requested database object could not be found. For example, an object store did not exist but was being opened.
  </code></pre>
  
  <p>How can I solve that?</p>