“Illegal Choice has been detected” I want to prevent validation check on the field_abc ?
How can I prevent validation for a field_abc

  function test_mail_menu() {
         $items['test-mail-1'] = array(
            'page callback' =&gt; 'drupal_get_form',
            'page arguments' =&gt; array('test_mail1_form'),
            'type' =&gt; MENU_CALLBACK,
            'access arguments' =&gt; array('access content'),
          );

    return $items;
    }
    function test_mail1_form ($form,$form_state) {
      $form = array();
      $form['field_abc'] = array(
        '#type' =&gt; 'textfield',
        '#title' =&gt; t('ABC'),
        '#validated' =&gt; TRUE,
     );

      $form['submit-button'] = array(
        '#type' =&gt; 'button',
        '#title' =&gt; t('sub'),
      );


      $form['#submit'][] = 'test_mail1_submit';
      $form['#validate'][] = 'test_mail1_validate';
      return $form;
    }

    function test_mail1_submit($form,&amp;$form_submit) {



    }

    function test_mail1_validate($form, &amp;$form_state) {



      if (!(is_numeric($form_state['input']['field_abc']))) {

        form_set_error('field_abc','ERROR');

      }
    }
If you don't want to validate that field, then remove the following function

function test_mail1_validate($form, &amp;$form_state) {



  if (!(is_numeric($form_state['input']['field_abc']))) {

    form_set_error('field_abc','ERROR');

  }
}


And remove the following line from test_mail1_form

$form['#validate'][] = 'test_mail1_validate';