gistfile1.js

//assign an observer to the submit button of the ajax form
this.addObserver("#btn-submit", "onclick", "Submit");

//only if we're passed validation, we show the overlay to display a request indicator
this.addObserver(this.getCommand("ValidateRules"), "onResponse", "ShowOverlay", { show: true });

//
this.addObserver(this.getCommand("Submit"), "onComplete", "ShowOverlay", { show: false });


//addintercepts
this.addIntercept("around", "Submit", "ValidateRules", {});


// command sequence:
// user clicks submit button -> validate the form -> if validation passes, show overlay -> hide overlay onComplete of submission