title: Using callback in another callback in Jquery
body: <p>i'm trying to another function after a function using call back in Jquery. 
  but i don't know why the second function doesn't work, it doesn't seem that i have any typo or something in my code can you help me out of this problem? </p>
  
  <p>here is my code. Thank you ! </p>
  
  <pre><code>$("#best_1").animate({'opacity':'0'},2000, function(){
    $("#best_1").removeClass("best_1", function(){
      $("#best_1").animate({'opacity':'1'},2000);
      $("#best_1").addClass("best_11");
  
    });
  });
  </code></pre>