Dynamic IFRAME Using Dynamic Document Fragment when html & css are provided as Strings

iframe.js

var html = '<h1 class="nar">Narendra</div>';
var css = '.nar { color: red; background: url("http://google.com/images/google_favicon_128.png") repeat scroll 0 0 transparent;}';
var nodeWhereToAppend = document.body;
//var nodeWhereToAppend = document.getElementById("container");

function CreateIframe(html, css, nodeWhereToAppend){
  var fragment = document.createDocumentFragment();
  var iframe = document.createElement('iframe');
  iframe.onload = function(){
      var doc = this.contentWindow.document;
      doc.body.innerHTML= html;
      var style = document.createElement("style");
      style.setAttribute("type","text/css");
      style.innerHTML = css;
      doc.head.appendChild(style);
  }
  fragment.appendChild(iframe);
  while (nodeWhereToAppend.firstChild) {
    nodeWhereToAppend.removeChild(nodeWhereToAppend.firstChild);
  }
  nodeWhereToAppend.appendChild(fragment);
}
CreateIframe(html, css, nodeWhereToAppend);