IE json bug

photos_controller.rb

class PhotosController < ApplicationController
  before_filter :authenticate_user!

  def create
    current_user.photo = params[:file] || params[:qqfile]

    data = if current_user.save
      {
        :success => true,
        :photo => {
          :original => current_user.photo.url,
          :avatar => current_user.photo.avatar.url
        }
      }
    else
      current_user.errors
    end

    respond_to do |format|
      format.json {
        render :json => "#{data.to_json}", :content_type => 'text/html'
      }
    end
  end
end

template.html.haml

%div.field.avatar
  - if current_user.photo.present?
    = image_tag current_user.photo.avatar.url, :id => 'original_photo'
  #upload{ :data => { :source => photo_path } }
    = f.file_field :photo

uploader.js

// with: https://github.com/valums/file-uploader
$(function() {
  var createUploader = function() {
    var $elem = $('#upload'), params = {};
    params[$('[name=csrf-param]').attr('content')] = $('[name=csrf-token]').attr('content');
    params['format'] = 'json';

    var uploader = new qq.FileUploader({
      element: $elem[0],
      action: $elem.data('source'),
      debug: false,
      onComplete: function(id, filename, responseJSON) {
        if (responseJSON.success) {
          $('#original_photo').attr('src', responseJSON['photo']['avatar']);
        }
      }
    });
    uploader.setParams(params);
  }
});