Alexander Netkachev has posted this great howto on his blog today, a look at making an Ajax login page with the help of the Dojo toolkit and the Zend Framework.
Article shows how to create Ajax forms with server-side actions using the Dojo toolkit and Zend Framework. It guides you through creation of a sample user login form that uses dojo.io client-side packages and Zend_Controller and Zend_Filter_Input server-side packages.
He talks about the situation that caused him to work up this model, including some of the other options he had looked into. He includes the code for the various pieces - the HTML for the view, the PHP for the controller, and the Javascript for the Dojo code and login action function.