FB.provide('Content', {
  postTarget: function(opts) {
    var form = document.createElement('form');
    form.action = opts.url;
    form.target = opts.target;
    form.method = 'POST';
    FB.Content.appendHidden(form);

    FB.Array.forEach(opts.params, function(val, key) {
      if (val !== null && val !== undefined) {
        var input = document.createElement('input');
        input.name = key;
        if (typeof val == "object"){
          input.value = JSON.stringify(val);
        } else {
          input.value = val;
        }
        form.appendChild(input);
      }
    });

    form.submit();
    form.parentNode.removeChild(form);
  }
}, true); //overwrite