title: Apply :focus for a class name in html css
body: <p>I have an input text box. On selecting the same, the highlighter(blue box around text box) appears. I need a single red line as border-bottom on input text box selection. Please see the code: </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>input:focus {
    background-color: yellow;
  }
  
  .myclass:focus {
    border-bottom: red;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;p&gt;Click inside the text fields to see a yellow background:&lt;/p&gt;
  
  &lt;form&gt;
    First input box: &lt;input class="myclass" type="text" name="firstname"&gt;&lt;br&gt; 
    Second input box: &lt;input type="text" name="lastname"&gt;
  &lt;/form&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>As I have multiple input textbox in my page and I want to apply style to only one textbox. So I can't use the input:focus code. How can I apply ':focus' to a particular class in css? Please help thanks in advance </p>