title: Dynamically changing the glyphicon of input add on
body: <p>How to change **glyphicon" (right side of input field (see below)) on validation of input type ?</p>
  
  <p>eg. When input <strong>is valid</strong>, change it to <strong>glyphicon-ok</strong> (tick mark ) or when it is invalid change it to <strong>glyphicon-remove</strong> ( cross sign )</p>
  
  <p><img src="https://i.stack.imgur.com/UaR9z.jpg" alt="enter image description here"></p>
  
  <pre><code>vm.rentalFields = [
      {
          key: 'first_name',
          type: 'input',
       //   class:glyphicon-ok,
  
          templateOptions: {
  
              type: 'text',
              label: 'First Name',
              placeholder: 'Enter your first name',
  
              required: true,
              "addonRight": {
                  "class": "glyphicon glyphicon-ok form-control-feedback"
                }
  
  
  
  
          }
      }];
  </code></pre>