js deferred test

function asyncEvent() {
  var dfd = new jQuery.Deferred();
  // Resolve after a random interval
  setTimeout(function() {
    dfd.resolve( "hurray" );
  }, Math.floor( 400 + Math.random() * 2000 ) );

// Return the Promise so caller can't change the Deferred
return dfd.promise();
}

// Attach a done, fail, and progress handler for the asyncEvent
$.when( asyncEvent() ).then(function( status) {
  $( "#content" ).append( status );
  }
  );