[jQuery] select the parent recursively

[Gill Bates]

current we have the html like following and I always want get element:
<span xmlns="asa"> started from the element <input>:

<span xmlns="asa">
   <span>
     <p>
      <input value="" size="10" class="exercise-input exercise-input-
formula" name="1"/>
     </p>
  </span>
</span>

or

<span xmlns="asa">
  <span></span>
   <span>
     <p>
      <input value="" size="10" class="exercise-input exercise-input-
formula" name="1"/>
     </p>
  </span>
</span>

so the only fixed element in this html is the input element and input
has a far far parent <span xmlns="asa">.
Now if I want select this <span xmlns="asa">, can I use some recursive
method like:

var $replace=jQuery("input");
                                        while($replace.attr("xmlns")!="asa"){
                                                $replace=$replace.parent();
                                                alert($replace.attr("xmlns"));
                                        }



apparently this code above doesn't work, but it's my idea.
Anyone could help?