title: hook_form_alter not saving values to database
body: <p>I'm altering a form made through admin panel using below code to copy text from first textarea to second. This is done by clicking on 'Copy' button. Frontend works well as expected. </p>
  
  <p>However when I submit the form using default submit button, values in textareas are not added to database. Therefore if I go to webform results from admin panel, I can't see any of the values.</p>
  
  <p>Do I need to add anything to custom submit handler for this?</p>
  
  <p>Thanks</p>
  
  <pre><code>function fence_quote_form_alter(&amp;$form, &amp;$form_state, $form_id) {
    if ($form_id == 'webform_client_form_1'){
      $form['input'] = array(
          '#type' =&gt; 'textarea',
          '#title' =&gt; t('Input text'),
          '#prefix' =&gt; '&lt;div id="in-text"&gt;',
          '#attributes' =&gt; array(
              'placeholder' =&gt; t('Enter some text here... '),
          ),
          '#suffix' =&gt; '&lt;/div&gt;',
      );
  
      $form['buttons']['fence_quote']  = array(
          '#type' =&gt; 'button',
          '#value' =&gt; t('Copy'),
          '#ajax' =&gt; array(
          'callback' =&gt; 'fence_quote_form_callback',
          'wrapper' =&gt; 'out-text',
          ),
      );
  
  
      $form['output'] = array(
          '#type' =&gt; 'textarea',
          '#title' =&gt; t('Output text:'),
          '#prefix' =&gt; '&lt;div id="out-text"&gt;',
          '#value' =&gt; '',
          '#attributes' =&gt; array(
              'placeholder' =&gt; t('Your text will appear here...'),
          ),
          '#suffix' =&gt; '&lt;/div&gt;',
      );
  
      $form['#validate'][] = 'mymodule_someform_custom_validation';
  
      $form['#submit'][] = 'my_custom_submit_function_submit';
  
  
    }
  
  }
  
  
  function fence_quote_form_callback($form, &amp;$form_state) {
    $form['output']['#value'] = $form_state['values']['input'];
    return $form['output']; 
  }
  
  
  function my_custom_submit_function_submit($form, &amp;$form_state) {
  
  }
  </code></pre>