placeholder on searchbox here is my template.php code:

function sizin_preprocess_page(&amp;$variables){
  $search_box = drupal_render(drupal_get_form('search_form'));
  $variables['search_box'] = $search_box;            
}  



function sizin_form_alter(&amp;$form, &amp;$form_state, $form_id) {
  if ($form_id == 'search_form') {
      // HTML5 placeholder attribute
      $form['search_form']['#attributes']['placeholder'] = t('Search ...');    
  }    
}  


and in my page.tpl code: 

  &lt;?php print $search_box; ?&gt;  


but I can't able to see placeholder. Any Idea?
Install Placeholder module. Using this module you can convert any label of any elements of any form in your site in to a placeholder. Just add the CSS style of the form element in to this module configuration and it will do the rest of the jobs



You can also try this

$form['search_form']['#attributes'] = array('placeholder' =&gt; 'Search ...');