Callback function from URL is not working

Question

When I create the function like this:

<script type="text/javascript">
  function mycallback(json) {
    for (var i = 0; i < json.feed.entry.length; i++) {
      for (var j = 0; j < json.feed.entry[i].link.length; j++) {
        if (json.feed.entry[i].link[j].rel == 'alternate') {
          var postUrl = json.feed.entry[i].link[j].href;
          break;
        }
      }
      var postTitle = json.feed.entry[i].title.$t;
      var postSummary = json.feed.entry[i].summary.$t;
      var item = '<div class="wrapper"><h3><a href=' + postUrl + '>' + postTitle + '</h3></a><p>' + postSummary + '</p></div>';
      document.write(item);
    }
  }
</script>

and whenever I put this script in any HTML element, it shows the recent post which is correct:

<script src="http://www.danpros.com/feeds/posts/summary/-/Blogger?max-results=5&alt=json-in-script&callback=mycallback"></script>

This is the fiddle for the above one its working. But I want to manipulate the script src attribute but I cant achieve the result from it:

<script type="text/javascript">
  function mycallback(json) {
    for (var i = 0; i < json.feed.entry.length; i++) {
      for (var j = 0; j < json.feed.entry[i].link.length; j++) {
        if (json.feed.entry[i].link[j].rel == 'alternate') {
          var postUrl = json.feed.entry[i].link[j].href;
          break;
        }
      }
      var postTitle = json.feed.entry[i].title.$t;
      var postSummary = json.feed.entry[i].summary.$t;
      var item = '<div class="wrapper"><h3><a href=' + postUrl + '>' + postTitle + '</h3></a><p>' + postSummary + '</p></div>';
      document.write(item);
    }
  }
</script>

<script>
    $(function(){
    var scriptSrc='http://www.danpros.com/feeds/posts/summary/-/Blogger?max-results=5&alt=json-in-script&callback=mycallback';
    $('.recent').append("<scri"+"pt src='"+scriptSrc+"'></scr"+"ipt>");
    });

</script>
<div class='recent'></div>

This is the fiddle for second one but not working.