title: Input validation for only alphabetical characters
body: <p>I want to validate my username input box that does not allows any number or special characters inside.
  My Html  </p>
  
  <pre><code>&lt;div class="form-group"&gt;
    &lt;input type="text" name="username" id="display_name" class="form-control input-lg"
    placeholder="User Name" tabindex="3"&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Javascript Validation </p>
  
  <pre><code>username: {
    required: true,
    minlength: 5,
    maxlength: 15,
    remote: "ajax_val/val_username.php",
    notNumber: true 
   },
  </code></pre>