$(function() {

  var url = 'http://jsbin.com/ocoteg/1';

  $.get(url).complete(function(xhr) {    

    var text = xhr.responseText;       

    var dom = $(text);

    console.log(dom);

    // Now I want to replace all links with a span and get the modified html text back

    dom.filter('a').each(function() {

      var el = $(this);

      var html = el.html();

      var span = $('<span/>').html(html);

      el.replaceWith(span);

    });

    console.log(dom);

    // So the links weren't replaced

    // How to get the modified string back

  });

});