title: Add Loading Icon before the submit button When Button is Disabled
body: <p>In my Detail Form there's on Submit Button
  on click I'm calling a Ajax request <br/>
  <a href="https://i.stack.imgur.com/VHEKj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VHEKj.png" alt="enter image description here" /></a></p>
  <p>while ajax request is processing my submit button is disabled <br/>
  <a href="https://i.stack.imgur.com/JxQxi.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JxQxi.png" alt="enter image description here" /></a></p>
  <p>What I want is to show loader icon like <code>fa-spinner fa-spin</code> when button is disabled <br/>
  <a href="https://i.stack.imgur.com/TdB2o.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TdB2o.png" alt="enter image description here" /></a></p>
  <p>here's a challenge  <br/></p>
  <ol>
  <li>I don't want to add any tag inside a button <code>&lt;button disabled&gt;...&lt;/button&gt;</code></li>
  <li>using only HTML, CSS, font-awesome</li>
  </ol>
  <p>I'm also trying to develop this, but I think I can get more good suggestion here.</p>
  <p><a href="https://jsfiddle.net/RaviMakwana/6q2jghLy/11/" rel="nofollow noreferrer">Here JsFiddle for basic start</a></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>body {
    background: #20262E;
    padding: 20px;
    font-family: Helvetica;
  }
  
  #banner-message {
    background: #fff;
    border-radius: 4px;
    padding: 20px;
    font-size: 25px;
    text-align: center;
    transition: all 0.2s;
    margin: 0 auto;
    width: 300px;
  }
  
  button {
    background: #0084ff;
    border: none;
    border-radius: 5px;
    padding: 8px 14px;
    font-size: 15px;
    color: #fff;
  }
  
  #banner-message.alt {
    background: #0084ff;
    color: #fff;
    margin-top: 40px;
    width: 200px;
  }
  
  #banner-message.alt button {
    background: #fff;
    color: #000;
  }
  
  button:disabled{
    opacity: 0.66
  } </code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.0/jquery.min.js"&gt;&lt;/script&gt;
  &lt;div id="banner-message"&gt;
    &lt;p&gt;Show loader on button Disabled&lt;/p&gt;
    &lt;button type="button" id="btnSubmit"&gt; Submit&lt;/button&gt; &lt;!-- should not change anything inside button tag, you can add class or property --&gt;
    &lt;br /&gt;
    &lt;label&gt;&lt;input type="checkbox" onchange="this.checked? $('#btnSubmit').attr('disabled','disabled'): $('#btnSubmit').removeAttr('disabled')" /&gt; Disable Button&lt;/label&gt;
    
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>