jQuery text fade/transition from one text to another?

You can use callbacks, like this:

$("#container").fadeOut(function() {
  $(this).text("World").fadeIn();
});

You can give it a try here, or because of how the queue works in this particular case, like this:

$("#container").fadeOut(function() {
  $(this).text("World")
}).fadeIn();

This executes the .text() call when the .fadeOut() is complete, just before fading in again.