JSONP Request Fails in IE6

fiddle.html

<a href="javascript:void(0);">click</a>
<div id="log"></div>

fiddle.js

$(function() {
  function log(message) {
    $('#log').append('<p>' + message + '</p>');
  }

  $('a').bind('click', function() {
    jQuery
      .ajax({
        url: 'http://search.twitter.com/search.json',
        dataType: 'jsonp',
        data: { q: 'hitsujiwool' }
      })
      .done(function(data) {
        log('ok');
      })
      .fail(function(a, b) {
        log('ng');
      });
  });
});