title: How can restrict the tab key press only within the modal popup when its open?
body: <p>I have a modal popup opened. I have accessibility requirement. So added ARIA related labels. But when i click tab key continuously focus going to the page behind the actual page.</p>
  
  <p><strong>Added role="dialog" in html file</strong></p>
  
  <p>But when modal opened i want only the focus navigate within the modal popup.</p>
  
  <p>Working on <code>Angular4, HTML5</code> project. <strong>Better if we find a solution within HTML file itself</strong>. <strong>I mean without added any javascript/jQuery related stuffs to prevent this</strong></p>