title: unknown error creating user with firebase
body: <p>I am receiving a CORS error from my browser while trying to implement a simple login authentication (email/password) with firebase. </p>
  
  <p>I checked the security rules and it is set to</p>
  
  <pre><code>{
  "rules": {
  ".read": true,
  ".write": true
   }
  }
  </code></pre>
  
  <p>Here's a summary of my code from the example.   </p>
  
  <pre><code>&lt;script src="https://cdn.firebase.com/js/client/1.0.15/firebase.js"&gt;&lt;/script&gt;
  &lt;script type='text/javascript' src='https://cdn.firebase.com/js/simple-login/1.5.0/firebase-simple-login.js'&gt; &lt;/script&gt;
  
  
  var myRootRef = new Firebase('https://vivid-fire-myserver.firebaseio.com/');
  var authClient = new FirebaseSimpleLogin(myRootRef, function(error, user) {
      if (error) {
          alert(error);
          return;
      }
      if (user) {
          alert('user already logged in');
      } else {
          alert('user logged out');
      }
  });
  
  $("#registerButton").on("click", function() {
      var email = $("#email").val();
      var password = $("#password").val();
      authClient.createUser(email, password, function(error,  user) {
          if (!error) {
              alert('registered successfully');
          } else {
              alert(error);
          }
      });
  }); 
  </code></pre>