title: Tabindex for elements inside iframe
body: <p>I have an iframe inside which is a form with an input element of type file and an image element.</p>
  
  <p>When using tab key it focuses on the iframe as a whole and does not focus on input box, the next press of tab focuses on the Browse button which appears for the input element of type file.</p>
  
  <p>My requirement is that when I press tab, focus goes on the input text box, then on browse button and finally to image element.</p>
  
  <p>I tried setting <code>tabindex</code> as 0 but it didn't work.</p>
  
  <p>Please suggest how to control the tab order through elements.</p>