How to check a div is exists or not?

Possible Duplicate:
Is there an “exists” function for jQuery

 <div class="XXX">
  <div class="created">
  </div>
</div>

div class="created" automatically generated by JavaScript using append function jQuery for some validation i need to check whether div is generated or not how can i do this.using jQuery.

something like $('.xxx').html()==' '