<script>
 $(document).ready(function(){
  $("#write_btn").click(function(){
                         if($("#contents").val() == '' ){
    alert('내용을 입력해주세요.');
    $("#contents").focus();
    return false;
   }else{
    $("#upload_action").submit();
   }
  });
 });
</script>

<textarea id="contents" cols='100' rows="25" name="contents"></textarea>

<script src="/ckeditor/ckeditor.js"></script>
<script>
 CKEDITOR.replace('contents');
</script>