jquery function on toggleClass complete?

jQuery has a promise method that returns a promise that resolves after all running animations on selected elements are complete. At that point, you can bind to it’s done method.

$("#loader").toggleClass('fadeOut',600).promise().done(function(){
    console.log('a');
});

http://jsfiddle.net/skram/4x76J/

Note: Animations using toggleClass require jQuery UI.