$form['#attached']['js'] = array('(function ($){$(document).ready(function() { $(".form-item-field-name input").focus()});})(jQuery);' => array( 'type' => 'inline'));

function your_module_form_alter(&$form, &$form_state, $form_id) {
  if($form_id == 'my_form'){
  // Add JavaScript file
  $form['#attached']['js'] = array(drupal_get_path('module', 'your_module') . '/your_file.js');

  // Or for inline JavaScript
  $form['#attached']['js'] = array('/* some javascript here */' => array( 'type' => 'inline'));
  }
}

function HOOK_form_user_login_alter(&$form, &$form_state, $form_id) {
    //should also add JS focus code for iOS Safari
    $form['name']['#attributes'] = array('autofocus' => '');
}