title: HtmlUnit can't get the js / ajax added of IFRAME
body: <p>I've just started learning <a href="http://htmlunit.sourceforge.net/" rel="nofollow">htmlunit</a> by gargoylesoftware and I have a problem.
  There is an iframe on a page, which appears after a button click. When i try to get this iframe by name I get a <code>ElementNotFoundException</code>. Also I tried <code>page.getFrames()</code> and it returns frames, but there is no frame that i'm looking for or it is blank. So It looks like js/ajax didn't update it. I work on jcpenny(dot)com and problem appears when I try to "checkout" from "My Bag" page
  Here is my WebClient settings</p>
  
  <pre><code>BrowserVersion bv = BrowserVersion.CHROME_16;
  bv.setUserAgent("Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)");
  CookieManager cm = new CookieManager();
  cm.clearCookies();
  cm.setCookiesEnabled(true);
  WebClient webClient = new WebClient(bv);
  webClient.setCookieManager(cm);
  webClient.setAjaxController(new NicelyResynchronizingAjaxController());
  webClient.setJavaScriptTimeout(15000);
  webClient.setCssErrorHandler(new SilentCssErrorHandler());
  webClient.getOptions().setJavaScriptEnabled(true);
  webClient.getOptions().setThrowExceptionOnScriptError(false);
  webClient.waitForBackgroundJavaScript(15000);
  webClient.getOptions().setThrowExceptionOnFailingStatusCode(false);
  webClient.getOptions().setRedirectEnabled(true);
  webClient.getOptions().setUseInsecureSSL(true);
  webClient.setRefreshHandler(new ThreadedRefreshHandler());
  </code></pre>