IE7 throws “parseerror” parsing JSON using jQuery

Question

IE7 throws an exception: "jquery: parseerror" when running the following code. It works in all other browsers I've tested (Firefox, Opera, Chrome, Chromium).

Script:

 function check(){
            $("#form").ajaxSubmit({
                url: "/send-file",
                dataType: "json",
                success:
                    function(answer){
                        $("#result").html(answer.msg);
                        },
                error:
                    function(jqXHR, textStatus, errorThrown){
                        alert(textStatus);

                    }
                });
            return false;
    }

The server script(controller of Pylons):

  @jsonify
    def sendFile(self):
        response.content_type = "text/plain"
        response.cache_control = 'no-cache'
        response.pragma = "no-cache, must-revalidate"
        response.expires = "-1" 

        data = dict(msg = '<h1 id="sd">ffffffffff</h1> \
                <p>ddddd</p> <a href="#">link</a>' )
        return data 

Answer 1

the problem seems to be in the jQuery plugin for uploading files using hidden frame. If it is the plugin, than it contains an error (if i recall correctly it reads the contents of the json from the body tag). I wanted to chat on the issue with the author, but the facebook comments in his blog raised an exception. As result, I slightly fixed the plugin locally to read the whole server result.

Unfortunatelly, I currently don't have access the hacked version.

Answer 2

instead if

response.content_type = "text/plain" 

try

response.content_type = "application/json"