title: Upload image with Jquery form plugin not working in IE8
body: <p>I am using jQuery form plugin in my MVC project for image uploading.</p>
  
  <p>The image upload works perfect in Chrome and firefox, however when it comes to IE 8.</p>
  
  <p>Not like Chrome, instead of returning json data which is later consumed by post-submit callback, in IE 8 it returns a txt file and ask you whether you want to download. and in side the txt file, it is the json data.</p>
  
  <p>couldn't figure out where did i do wrong, any ideas?</p>
  
  <p>thanks in advance.</p>
  
  <p>Code is placed in a seperated js file:
  <strong>upload.js</strong></p>
  
  <pre><code>(function ($) {
  ImageUploader = function (o) {
  
          var options = {
  
  
              success: showResponse,  // post-submit callback 
  
              url:    "/Image/ImageUpload",         // override for form's 'action' attribute 
              type:      "post",        // 'get' or 'post', override for form's 'method' attribute 
              dataType: 'json',        // 'xml', 'script', or 'json' (expected server response type) 
              clearForm: true        // clear all form fields after successful submit 
  
          };
  
          o.ajaxForm(options);
  
          $("input#file").change(function () {
              o.submit();
          });
  
  // post-submit callback 
          function showResponse(responseText, statusText, xhr, $form) {
          ....
      }
   };
  })(jQuery);
  </code></pre>
  
  <p>on page view:</p>
  
  <pre><code>$(document).ready(function () {
  ImageUploader($("#ajaxUploadForm"));
  });
  </code></pre>