title: How do I change 'src' of an iframe from another page onclick?
body: <p>I have two html pages <code>1.html</code> and <code>2.html</code>.</p>
  
  <p>I have two buttons on <code>1.html</code>.</p>
  
  <ul>
  <li>one button links to Google </li>
  <li>one button links to Facebook</li>
  </ul>
  
  <p>I have an <code>iframe</code> in <code>2.html</code>.</p>
  
  <p>How do I change the <code>iframe src</code> on <code>2.html</code> by clicking on a button on <code>1.html</code>.</p>