I'm trying to parse a json string embedded in my html file. 
Here is the reduced code.

```
<html>
<head>
<script src="./jquery-1.4.4.min.js" type="text/javascript"></script>
<script>
  function parse_json(){
    var jtext = $("#mtxt").text();
    var jdata = jQuery.parseJSON(jtext);
    JSON.parse(JSON.stringify(jdata), function (key, value){ 
            alert("key=" + key + " value=" + value);
            if(key== ""){
                    alert("value in string" + JSON.stringify(value));              
            }
    });
  }
  $(document).ready(function() {
    $("#run").click( function () {
        parse_json();
    }); 
  });
</script>
</head>

<body>
<a id="run" href="#">run</a>
<div id="mtxt">
{"caller": "539293493"}
</div>
</body>
</html>

```

When I parse it, apart from the expected "caller" value, I get an extra empty "key" and "value". 
The first alert gives me 

```
key= value=[object Object]

```

The second alert gives me

```
value in string{}

```

What is happening? Why this extra entry?