title: How to get a <img> tag the focus
body: <p>I have below code in html page:</p>
  
  <pre><code>&lt;img id="image_java"  alt="image_not" src="images/java-icon.png"&gt;
  </code></pre>
  
  <p>in css page the below code:</p>
  
  <pre><code>#image_java: focus {
  outline: 2px solid blue;
  }
  </code></pre>
  
  <p>I have also tried:</p>
  
  <pre><code>img:focus{
  outline: 2px solid blue;
  </code></pre>
  
  <p>}</p>
  
  <p>but non of them seem to work, they are suppose to display a blue margin around the image when focus.
  Does any one know how to do that?  thank you!!!</p>