Make custom Ajax form validation for form submittion

function mycustom_menu(){
$items['mycustom'] = array(
	'title'=>t('Mymenu'),
	'page callback'=>'mycustomform',
	/* 'page arguments' => array('mycustomform'), */
	 'access callback'=> TRUE,
	'type'=> MENU_CALLBACK
);
return $items;
}

function mycustomform($form, &$form_state) {

  $form["wrapper"] = array("#markup" => "<div class='inline-messages'></div>");

  $form["name"] = array(
    "#type" => "textfield", 
    "#required" => true,
    "#title" => "Name"
  );

  $form["submit"] = array(
    "#type" => "submit", 
    "#value" => "Send", 
    "#ajax" => array(
      "callback" => "productsearchbar_savesearch_form_callback", 
      "wrapper" => "mycustomform", 
      "effect" => "fade"
    )
  );

  return $form;
}

function productsearchbar_savesearch_form_callback($form, &$form_state) {
  $messages = theme('status_messages');

  if($messages){
    $form["wrapper"] = array("#markup" => "<div class='inline-messages'>$messages</div>");
  }
  return $form;
}

function productsearchbar_savesearch_form_validate($form, &$form_state) {
  if ($form_state['values']['name'] == '') {
   form_set_error('', t('Name field is empty!'));
  }
}

function mycustomform_submit($form, &$form_state) {
  drupal_set_message(t('Your form has been saved.'));
}