How do I change the html for dynamically added content

How do I change the html for dynamically added content

On my site there is a dynamically created popup.

Unfortunately I don't have access to the code that creates it, but I want to change the html after it is loaded like this

  1. $('.check_out').html('<div id="text">Check Out </div><div class="arrow-right"></div>');
    $('.continue_shopping').html('<div id="text">Continue Shopping </div><div class="arrow-right"></div>');

I am restricted to jquery version 1.4.2. How do I do this?